path: root/Documentation/scsi/ibmmca.txt
diff options
Diffstat (limited to 'Documentation/scsi/ibmmca.txt')
1 files changed, 1402 insertions, 0 deletions
diff --git a/Documentation/scsi/ibmmca.txt b/Documentation/scsi/ibmmca.txt
new file mode 100644
index 000000000000..2814491600ff
--- /dev/null
+++ b/Documentation/scsi/ibmmca.txt
@@ -0,0 +1,1402 @@
+ -=< The IBM Microchannel SCSI-Subsystem >=-
+ for the IBM PS/2 series
+ Low Level Software-Driver for Linux
+ Copyright (c) 1995 Strom Systems, Inc. under the terms of the GNU
+ General Public License. Originally written by Martin Kolinek, December 1995.
+ Officially modified and maintained by Michael Lang since January 1999.
+ Version 4.0a
+ Last update: January 3, 2001
+ Before you Start
+ ----------------
+ This is the common README.ibmmca file for all driver releases of the
+ IBM MCA SCSI driver for Linux. Please note, that driver releases 4.0
+ or newer do not work with kernel versions older than 2.4.0, while driver
+ versions older than 4.0 do not work with kernels 2.4.0 or later! If you
+ try to compile your kernel with the wrong driver source, the
+ compilation is aborted and you get a corresponding error message. This is
+ no bug in the driver. It prevents you from using the wrong sourcecode
+ with the wrong kernel version.
+ Authors of this Driver
+ ----------------------
+ - Chris Beauregard (improvement of the SCSI-device mapping by the driver)
+ - Martin Kolinek (origin, first release of this driver)
+ - Klaus Kudielka (multiple SCSI-host management/detection, adaption to
+ Linux Kernel 2.1.x, module support)
+ - Michael Lang (assigning original pun/lun mapping, dynamical ldn
+ assignment, rewritten adapter detection, this file,
+ patches, official driver maintenance and subsequent
+ debugging, related with the driver)
+ Table of Contents
+ -----------------
+ 1 Abstract
+ 2 Driver Description
+ 2.1 IBM SCSI-Subsystem Detection
+ 2.2 Physical Units, Logical Units, and Logical Devices
+ 2.3 SCSI-Device Recognition and dynamical ldn Assignment
+ 2.4 SCSI-Device Order
+ 2.5 Regular SCSI-Command-Processing
+ 2.6 Abort & Reset Commands
+ 2.7 Disk Geometry
+ 2.8 Kernel Boot Option
+ 2.9 Driver Module Support
+ 2.10 Multiple Hostadapter Support
+ 2.11 /proc/scsi-Filesystem Information
+ 2.12 /proc/mca-Filesystem Information
+ 2.13 Supported IBM SCSI-Subsystems
+ 2.14 Linux Kernel Versions
+ 3 Code History
+ 4 To do
+ 5 Users' Manual
+ 5.1 Commandline Parameters
+ 5.2 Troubleshooting
+ 5.3 Bugreports
+ 5.4 Support WWW-page
+ 6 References
+ 7 Credits to
+ 7.1 People
+ 7.2 Sponsors & Supporters
+ 8 Trademarks
+ 9 Disclaimer
+ * * *
+ 1 Abstract
+ ----------
+ This README-file describes the IBM SCSI-subsystem low level driver for
+ Linux. The descriptions which were formerly kept in the source-code have
+ been taken out to this file to easify the codes' readability. The driver
+ description has been updated, as most of the former description was already
+ quite outdated. The history of the driver development is also kept inside
+ here. Multiple historical developments have been summarized to shorten the
+ textsize a bit. At the end of this file you can find a small manual for
+ this driver and hints to get it running on your machine.
+ 2 Driver Description
+ --------------------
+ 2.1 IBM SCSI-Subsystem Detection
+ --------------------------------
+ This is done in the ibmmca_detect() function. It first checks, if the
+ Microchannel-bus support is enabled, as the IBM SCSI-subsystem needs the
+ Microchannel. In a next step, a free interrupt is chosen and the main
+ interrupt handler is connected to it to handle answers of the SCSI-
+ subsystem(s). If the F/W SCSI-adapter is forced by the BIOS to use IRQ11
+ instead of IRQ14, IRQ11 is used for the IBM SCSI-2 F/W adapter. In a
+ further step it is checked, if the adapter gets detected by force from
+ the kernel commandline, where the I/O port and the SCSI-subsystem id can
+ be specified. The next step checks if there is an integrated SCSI-subsystem
+ installed. This register area is fixed through all IBM PS/2 MCA-machines
+ and appears as something like a virtual slot 10 of the MCA-bus. On most
+ PS/2 machines, the POS registers of slot 10 are set to 0xff or 0x00 if not
+ integrated SCSI-controller is available. But on certain PS/2s, like model
+ 9595, this slot 10 is used to store other information which at earlier
+ stage confused the driver and resulted in the detection of some ghost-SCSI.
+ If POS-register 2 and 3 are not 0x00 and not 0xff, but all other POS
+ registers are either 0xff or 0x00, there must be an integrated SCSI-
+ subsystem present and it will be registered as IBM Integrated SCSI-
+ Subsystem. The next step checks, if there is a slot-adapter installed on
+ the MCA-bus. To get this, the first two POS-registers, that represent the
+ adapter ID are checked. If they fit to one of the ids, stored in the
+ adapter list, a SCSI-subsystem is assumed to be found in a slot and will be
+ registered. This check is done through all possible MCA-bus slots to allow
+ more than one SCSI-adapter to be present in the PS/2-system and this is
+ already the first point of problems. Looking into the technical reference
+ manual for the IBM PS/2 common interfaces, the POS2 register must have
+ different interpretation of its single bits to avoid overlapping I/O
+ regions. While one can assume, that the integrated subsystem has a fix
+ I/O-address at 0x3540 - 0x3547, further installed IBM SCSI-adapters must
+ use a different I/O-address. This is expressed by bit 1 to 3 of POS2
+ (multiplied by 8 + 0x3540). Bits 2 and 3 are reserved for the integrated
+ subsystem, but not for the adapters! The following list shows, how the
+ bits of POS2 and POS3 should be interpreted.
+ The POS2-register of all PS/2 models' integrated SCSI-subsystems has the
+ following interpretation of bits:
+ Bit 7 - 4 : Chip Revision ID (Release)
+ Bit 3 - 2 : Reserved
+ Bit 1 : 8k NVRAM Disabled
+ Bit 0 : Chip Enable (EN-Signal)
+ The POS3-register is interpreted as follows (for most IBM SCSI-subsys.):
+ Bit 7 - 5 : SCSI ID
+ Bit 4 - 0 : Reserved = 0
+ The slot-adapters have different interpretation of these bits. The IBM SCSI
+ adapter (w/Cache) and the IBM SCSI-2 F/W adapter use the following
+ interpretation of the POS2 register:
+ Bit 7 - 4 : ROM Segment Address Select
+ Bit 3 - 1 : Adapter I/O Address Select (*8+0x3540)
+ Bit 0 : Adapter Enable (EN-Signal)
+ and for the POS3 register:
+ Bit 7 - 5 : SCSI ID
+ Bit 4 : Fairness Enable (SCSI ID3 f. F/W)
+ Bit 3 - 0 : Arbitration Level
+ The most modern product of the series is the IBM SCSI-2 F/W adapter, it
+ allows dual-bus SCSI and SCSI-wide addressing, which means, PUNs may be
+ between 0 and 15. Here, Bit 4 is the high-order bit of the 4-bit wide
+ adapter PUN expression. In short words, this means, that IBM PS/2 machines
+ can only support 1 single integrated subsystem by default. Additional
+ slot-adapters get ports assigned by the automatic configuration tool.
+ One day I found a patch in ibmmca_detect(), forcing the I/O-address to be
+ 0x3540 for integrated SCSI-subsystems, there was a remark placed, that on
+ integrated IBM SCSI-subsystems of model 56, the POS2 register was showing 5.
+ This means, that really for these models, POS2 has to be interpreted
+ sticking to the technical reference guide. In this case, the bit 2 (4) is
+ a reserved bit and may not be interpreted. These differences between the
+ adapters and the integrated controllers are taken into account by the
+ detection routine of the driver on from version >3.0g.
+ Every time, a SCSI-subsystem is discovered, the ibmmca_register() function
+ is called. This function checks first, if the requested area for the I/O-
+ address of this SCSI-subsystem is still available and assigns this I/O-
+ area to the SCSI-subsystem. There are always 8 sequential I/O-addresses
+ taken for each individual SCSI-subsystem found, which are:
+ Offset Type Permissions
+ 0 Command Interface Register 1 Read/Write
+ 1 Command Interface Register 2 Read/Write
+ 2 Command Interface Register 3 Read/Write
+ 3 Command Interface Register 4 Read/Write
+ 4 Attention Register Read/Write
+ 5 Basic Control Register Read/Write
+ 6 Interrupt Status Register Read
+ 7 Basic Status Register Read
+ After the I/O-address range is assigned, the host-adapter is assigned
+ to a local structure which keeps all adapter information needed for the
+ driver itself and the mid- and higher-level SCSI-drivers. The SCSI pun/lun
+ and the adapters' ldn tables are initialized and get probed afterwards by
+ the check_devices() function. If no further adapters are found,
+ ibmmca_detect() quits.
+ 2.2 Physical Units, Logical Units, and Logical Devices
+ ------------------------------------------------------
+ There can be up to 56 devices on the SCSI bus (besides the adapter):
+ there are up to 7 "physical units" (each identified by physical unit
+ number or pun, also called the scsi id, this is the number you select
+ with hardware jumpers), and each physical unit can have up to 8
+ "logical units" (each identified by logical unit number, or lun,
+ between 0 and 7). The IBM SCSI-2 F/W adapter offers this on up to two
+ busses and provides support for 30 logical devices at the same time, where
+ in wide-addressing mode you can have 16 puns with 32 luns on each device.
+ This section dexribes you the handling of devices on non-F/W adapters.
+ Just imagine, that you can have 16 * 32 = 512 devices on a F/W adapter
+ which means a lot of possible devices for such a small machine.
+ Typically the adapter has pun=7, so puns of other physical units
+ are between 0 and 6(15). On a wide-adapter a pun higher than 7 is
+ possible, but is normally not used. Almost all physical units have only
+ one logical unit, with lun=0. A CD-ROM jukebox would be an example of a
+ physical unit with more than one logical unit.
+ The embedded microprocessor of the IBM SCSI-subsystem hides the complex
+ two-dimensional (pun,lun) organization from the operating system.
+ When the machine is powered-up (or rebooted), the embedded microprocessor
+ checks, on its own, all 56 possible (pun,lun) combinations, and the first
+ 15 devices found are assigned into a one-dimensional array of so-called
+ "logical devices", identified by "logical device numbers" or ldn. The last
+ ldn=15 is reserved for the subsystem itself. Wide adapters may have
+ to check up to 15 * 8 = 120 pun/lun combinations.
+ 2.3 SCSI-Device Recognition and Dynamical ldn Assignment
+ --------------------------------------------------------
+ One consequence of information hiding is that the real (pun,lun)
+ numbers are also hidden. The two possibilities to get around this problem
+ is to offer fake pun/lun combinations to the operating system or to
+ delete the whole mapping of the adapter and to reassign the ldns, using
+ the immediate assign command of the SCSI-subsystem for probing through
+ all possible pun/lun combinations. a ldn is a "logical device number"
+ which is used by IBM SCSI-subsystems to access some valid SCSI-device.
+ At the beginning of the development of this driver, the following approach
+ was used:
+ First, the driver checked the ldn's (0 to 6) to find out which ldn's
+ have devices assigned. This was done by the functions check_devices() and
+ device_exists(). The interrupt handler has a special paragraph of code
+ (see local_checking_phase_flag) to assist in the checking. Assume, for
+ example, that three logical devices were found assigned at ldn 0, 1, 2.
+ These are presented to the upper layer of Linux SCSI driver
+ as devices with bogus (pun, lun) equal to (0,0), (1,0), (2,0).
+ On the other hand, if the upper layer issues a command to device
+ say (4,0), this driver returns DID_NO_CONNECT error.
+ In a second step of the driver development, the following improvement has
+ been applied: The first approach limited the number of devices to 7, far
+ fewer than the 15 that it could usem then it just maped ldn ->
+ (ldn/8,ldn%8) for pun,lun. We ended up with a real mishmash of puns
+ and luns, but it all seemed to work.
+ The latest development, which is implemented from the driver version 3.0
+ and later, realizes the device recognition in the following way:
+ The physical SCSI-devices on the SCSI-bus are probed via immediate_assign-
+ and device_inquiry-commands, that is all implemented in a completely new
+ made check_devices() subroutine. This delivers an exact map of the physical
+ SCSI-world that is now stored in the get_scsi[][]-array. This means,
+ that the once hidden pun,lun assignment is now known to this driver.
+ It no longer believes in default-settings of the subsystem and maps all
+ ldns to existing pun,lun "by foot". This assures full control of the ldn
+ mapping and allows dynamical remapping of ldns to different pun,lun, if
+ there are more SCSI-devices installed than ldns available (n>15). The
+ ldns from 0 to 6 get 'hardwired' by this driver to puns 0 to 7 at lun=0,
+ excluding the pun of the subsystem. This assures, that at least simple
+ SCSI-installations have optimum access-speed and are not touched by
+ dynamical remapping. The ldns 7 to 14 are put to existing devices with
+ lun>0 or to non-existing devices, in order to satisfy the subsystem, if
+ there are less than 15 SCSI-devices connected. In the case of more than 15
+ devices, the dynamical mapping goes active. If the get_scsi[][] reports a
+ device to be existant, but it has no ldn assigned, it gets a ldn out of 7
+ to 14. The numbers are assigned in cyclic order. Therefore it takes 8
+ dynamical reassignments on the SCSI-devices, until a certain device
+ loses its ldn again. This assures, that dynamical remapping is avoided
+ during intense I/O between up to 15 SCSI-devices (means pun,lun
+ combinations). A further advantage of this method is, that people who
+ build their kernel without probing on all luns will get what they expect,
+ because the driver just won't assign everything with lun>0 when
+ multpile lun probing is inactive.
+ 2.4 SCSI-Device Order
+ ---------------------
+ Because of the now correct recognition of physical pun,lun, and
+ their report to mid-level- and higher-level-drivers, the new reported puns
+ can be different from the old, faked puns. Therefore, Linux will eventually
+ change /dev/sdXXX assignments and prompt you for corrupted superblock
+ repair on boottime. In this case DO NOT PANIC, YOUR DISKS ARE STILL OK!!!
+ You have to reboot (CTRL-D) with an old kernel and set the /etc/fstab-file
+ entries right. After that, the system should come up as errorfree as before.
+ If your boot-partition is not coming up, also edit the /etc/lilo.conf-file
+ in a Linux session booted on old kernel and run lilo before reboot. Check
+ lilo.conf anyway to get boot on other partitions with foreign OSes right
+ again. But there exists a feature of this driver that allows you to change
+ the assignment order of the SCSI-devices by flipping the PUN-assignment.
+ See the next paragraph for a description.
+ The problem for this is, that Linux does not assign the SCSI-devices in the
+ way as described in the ANSI-SCSI-standard. Linux assigns /dev/sda to
+ the device with at minimum id 0. But the first drive should be at id 6,
+ because for historical reasons, drive at id 6 has, by hardware, the highest
+ priority and a drive at id 0 the lowest. IBM was one of the rare producers,
+ where the BIOS assigns drives belonging to the ANSI-SCSI-standard. Most
+ other producers' BIOS does not (I think even Adaptec-BIOS). The
+ IBMMCA_SCSI_ORDER_STANDARD flag, which you set while configuring the
+ kernel enables to choose the preferred way of SCSI-device-assignment.
+ Defining this flag would result in Linux determining the devices in the
+ same order as DOS and OS/2 does on your MCA-machine. This is also standard
+ on most industrial computers and OSes, like e.g. OS-9. Leaving this flag
+ undefined will get your devices ordered in the default way of Linux. See
+ also the remarks of Chris Beauregard from Dec 15, 1997 and the followups
+ in section 3.
+ 2.5 Regular SCSI-Command-Processing
+ -----------------------------------
+ Only three functions get involved: ibmmca_queuecommand(), issue_cmd(),
+ and interrupt_handler().
+ The upper layer issues a scsi command by calling function
+ ibmmca_queuecommand(). This function fills a "subsystem control block"
+ (scb) and calls a local function issue_cmd(), which writes a scb
+ command into subsystem I/O ports. Once the scb command is carried out,
+ the interrupt_handler() is invoked. If a device is determined to be
+ existant and it has not assigned any ldn, it gets one dynamically.
+ For this, the whole stuff is done in ibmmca_queuecommand().
+ 2.6 Abort & Reset Commands
+ --------------------------
+ These are implemented with busy waiting for interrupt to arrive.
+ ibmmca_reset() and ibmmca_abort() do not work sufficently well
+ up to now and need still a lot of development work. But, this seems
+ to be even a problem with other SCSI-low level drivers, too. However,
+ this should be no excuse.
+ 2.7 Disk Geometry
+ -----------------
+ The ibmmca_biosparams() function should return the same disk geometry
+ as the bios. This is needed for fdisk, etc. The returned geometry is
+ certainly correct for disks smaller than 1 gigabyte. In the meantime,
+ it has been proved, that this works fine even with disks larger than
+ 1 gigabyte.
+ 2.8 Kernel Boot Option
+ ----------------------
+ The function ibmmca_scsi_setup() is called if option ibmmcascsi=n
+ is passed to the kernel. See file linux/init/main.c for details.
+ 2.9 Driver Module Support
+ -------------------------
+ Is implemented and tested by K. Kudielka. This could probably not work
+ on kernels <2.1.0.
+ 2.10 Multiple Hostadapter Support
+ ---------------------------------
+ This driver supports up to eight interfaces of type IBM-SCSI-Subsystem.
+ Integrated-, and MCA-adapters are automatically recognized. Unrecognizable
+ IBM-SCSI-Subsystem interfaces can be specified as kernel-parameters.
+ 2.11 /proc/scsi-Filesystem Information
+ --------------------------------------
+ Information about the driver condition is given in
+ /proc/scsi/ibmmca/<host_no>. ibmmca_proc_info() provides this information.
+ This table is quite informative for interested users. It shows the load
+ of commands on the subsystem and wether you are running the bypassed
+ (software) or integrated (hardware) SCSI-command set (see below). The
+ amount of accesses is shown. Read, write, modeselect is shown separately
+ in order to help debugging problems with CD-ROMs or tapedrives.
+ The following table shows the list of 15 logical device numbers, that are
+ used by the SCSI-subsystem. The load on each ldn is shown in the table,
+ again, read and write commands are split. The last column shows the amount
+ of reassignments, that have been applied to the ldns, if you have more than
+ 15 pun/lun combinations available on the SCSI-bus.
+ The last two tables show the pun/lun map and the positions of the ldns
+ on this pun/lun map. This may change during operation, when a ldn is
+ reassigned to another pun/lun combination. If the necessity for dynamical
+ assignments is set to 'no', the ldn structure keeps static.
+ 2.12 /proc/mca-Filesystem Information
+ -------------------------------------
+ The slot-file contains all default entries and in addition chip and I/O-
+ address information of the SCSI-subsystem. This information is provided
+ by ibmmca_getinfo().
+ 2.13 Supported IBM SCSI-Subsystems
+ ----------------------------------
+ The following IBM SCSI-subsystems are supported by this driver:
+ - IBM Fast/Wide SCSI-2 Adapter
+ - IBM 7568 Industrial Computer SCSI Adapter w/Cache
+ - IBM Expansion Unit SCSI Controller
+ - IBM SCSI Adapter w/Cache
+ - IBM SCSI Adapter
+ - IBM Integrated SCSI Controller
+ - All clones, 100% compatible with the chipset and subsystem command
+ system of IBM SCSI-adapters (forced detection)
+ 2.14 Linux Kernel Versions
+ --------------------------
+ The IBM SCSI-subsystem low level driver is prepared to be used with
+ all versions of Linux between 2.0.x and 2.4.x. The compatibility checks
+ are fully implemented up from version 3.1e of the driver. This means, that
+ you just need the latest ibmmca.h and ibmmca.c file and copy it in the
+ linux/drivers/scsi directory. The code is automatically adapted during
+ kernel compilation. This is different from kernel 2.4.0! Here version
+ 4.0 or later of the driver must be used for kernel 2.4.0 or later. Version
+ 4.0 or later does not work together with older kernels! Driver versions
+ older than 4.0 do not work together with kernel 2.4.0 or later. They work
+ on all older kernels.
+ 3 Code History
+ --------------
+ Jan 15 1996: First public release.
+ - Martin Kolinek
+ Jan 23 1996: Scrapped code which reassigned scsi devices to logical
+ device numbers. Instead, the existing assignment (created
+ when the machine is powered-up or rebooted) is used.
+ A side effect is that the upper layer of Linux SCSI
+ device driver gets bogus scsi ids (this is benign),
+ and also the hard disks are ordered under Linux the
+ same way as they are under dos (i.e., C: disk is sda,
+ D: disk is sdb, etc.).
+ - Martin Kolinek
+ I think that the CD-ROM is now detected only if a CD is
+ inside CD_ROM while Linux boots. This can be fixed later,
+ once the driver works on all types of PS/2's.
+ - Martin Kolinek
+ Feb 7 1996: Modified biosparam function. Fixed the CD-ROM detection.
+ For now, devices other than harddisk and CD_ROM are
+ ignored. Temporarily modified abort() function
+ to behave like reset().
+ - Martin Kolinek
+ Mar 31 1996: The integrated scsi subsystem is correctly found
+ in PS/2 models 56,57, but not in model 76. Therefore
+ the ibmmca_scsi_setup() function has been added today.
+ This function allows the user to force detection of
+ scsi subsystem. The kernel option has format
+ ibmmcascsi=n
+ where n is the scsi_id (pun) of the subsystem. Most likely, n is 7.
+ - Martin Kolinek
+ Aug 21 1996: Modified the code which maps ldns to (pun,0). It was
+ insufficient for those of us with CD-ROM changers.
+ - Chris Beauregard
+ Dec 14 1996: More improvements to the ldn mapping. See check_devices
+ for details. Did more fiddling with the integrated SCSI detection,
+ but I think it's ultimately hopeless without actually testing the
+ model of the machine. The 56, 57, 76 and 95 (ultimedia) all have
+ different integrated SCSI register configurations. However, the 56
+ and 57 are the only ones that have problems with forced detection.
+ - Chris Beauregard
+ Mar 8-16 1997: Modified driver to run as a module and to support
+ multiple adapters. A structure, called ibmmca_hostdata, is now
+ present, containing all the variables, that were once only
+ available for one single adapter. The find_subsystem-routine has vanished.
+ The hardware recognition is now done in ibmmca_detect directly.
+ This routine checks for presence of MCA-bus, checks the interrupt
+ level and continues with checking the installed hardware.
+ Certain PS/2-models do not recognize a SCSI-subsystem automatically.
+ Hence, the setup defined by command-line-parameters is checked first.
+ Thereafter, the routine probes for an integrated SCSI-subsystem.
+ Finally, adapters are checked. This method has the advantage to cover all
+ possible combinations of multiple SCSI-subsystems on one MCA-board. Up to
+ eight SCSI-subsystems can be recognized and announced to the upper-level
+ drivers with this improvement. A set of defines made changes to other
+ routines as small as possible.
+ - Klaus Kudielka
+ May 30 1997: (v1.5b)
+ 1) SCSI-command capability enlarged by the recognition of MODE_SELECT.
+ This needs the RD-Bit to be disabled on IM_OTHER_SCSI_CMD_CMD which
+ allows data to be written from the system to the device. It is a
+ necessary step to be allowed to set blocksize of SCSI-tape-drives and
+ the tape-speed, whithout confusing the SCSI-Subsystem.
+ 2) The recognition of a tape is included in the check_devices routine.
+ This is done by checking for TYPE_TAPE, that is already defined in
+ the kernel-scsi-environment. The markup of a tape is done in the
+ global ldn_is_tape[] array. If the entry on index ldn
+ is 1, there is a tapedrive connected.
+ 3) The ldn_is_tape[] array is necessary to distinguish between tape- and
+ other devices. Fixed blocklength devices should not cause a problem
+ with the SCB-command for read and write in the ibmmca_queuecommand
+ subroutine. Therefore, I only derivate the READ_XX, WRITE_XX for
+ the tape-devices, as recommended by IBM in this Technical Reference,
+ mentioned below. (IBM recommends to avoid using the read/write of the
+ subsystem, but the fact was, that read/write causes a command error from
+ the subsystem and this causes kernel-panic.)
+ 4) In addition, I propose to use the ldn instead of a fix char for the
+ display of PS2_DISK_LED_ON(). On 95, one can distinguish between the
+ devices that are accessed. It shows activity and easyfies debugging.
+ The tape-support has been tested with a SONY SDT-5200 and a HP DDS-2
+ (I do not know yet the type). Optimization and CD-ROM audio-support,
+ I am working on ...
+ - Michael Lang
+ June 19 1997: (v1.6b)
+ 1) Submitting the extra-array ldn_is_tape[] -> to the local ld[]
+ device-array.
+ 2) CD-ROM Audio-Play seems to work now.
+ 3) When using DDS-2 (120M) DAT-Tapes, mtst shows still density-code
+ 0x13 for ordinary DDS (61000 BPM) instead 0x24 for DDS-2. This appears
+ also on Adaptec 2940 adaptor in a PCI-System. Therefore, I assume that
+ the problem is independent of the low-level-driver/bus-architecture.
+ 4) Hexadecimal ldn on PS/2-95 LED-display.
+ 5) Fixing of the PS/2-LED on/off that it works right with tapedrives and
+ does not confuse the disk_rw_in_progress counter.
+ - Michael Lang
+ June 21 1997: (v1.7b)
+ 1) Adding of a proc_info routine to inform in /proc/scsi/ibmmca/<host> the
+ outer-world about operational load statistics on the different ldns,
+ seen by the driver. Everybody that has more than one IBM-SCSI should
+ test this, because I only have one and cannot see what happens with more
+ than one IBM-SCSI hosts.
+ 2) Definition of a driver version-number to have a better recognition of
+ the source when there are existing too much releases that may confuse
+ the user, when reading about release-specific problems. Up to know,
+ I calculated the version-number to be 1.7. Because we are in BETA-test
+ yet, it is today 1.7b.
+ 3) Sorry for the heavy bug I programmed on June 19 1997! After that, the
+ CD-ROM did not work any more! The C7-command was a fake impression
+ I got while programming. Now, the READ and WRITE commands for CD-ROM are
+ no longer running over the subsystem, but just over
+ IM_OTHER_SCSI_CMD_CMD. On my observations (PS/2-95), now CD-ROM mounts
+ much faster(!) and hopefully all fancy multimedia-functions, like direct
+ digital recording from audio-CDs also work. (I tried it with cdda2wav
+ from the cdwtools-package and it filled up the harddisk immediately :-).)
+ To easify boolean logics, a further local device-type in ld[], called
+ is_cdrom has been included.
+ 4) If one uses a SCSI-device of unsupported type/commands, one
+ immediately runs into a kernel-panic caused by Command Error. To better
+ understand which SCSI-command caused the problem, I extended this
+ specific panic-message slightly.
+ - Michael Lang
+ June 25 1997: (v1.8b)
+ 1) Some cosmetical changes for the handling of SCSI-device-types.
+ Now, also CD-Burners / WORMs and SCSI-scanners should work. For
+ MO-drives I have no experience, therefore not yet supported.
+ In logical_devices I changed from different type-variables to one
+ called 'device_type' where the values, corresponding to scsi.h,
+ of a SCSI-device are stored.
+ 2) There existed a small bug, that maps a device, coming after a SCSI-tape
+ wrong. Therefore, e.g. a CD-ROM changer would have been mapped wrong
+ -> problem removed.
+ 3) Extension of the logical_device structure. Now it contains also device,
+ vendor and revision-level of a SCSI-device for internal usage.
+ - Michael Lang
+ June 26-29 1997: (v2.0b)
+ 1) The release number 2.0b is necessary because of the completely new done
+ recognition and handling of SCSI-devices with the adapter. As I got
+ from Chris the hint, that the subsystem can reassign ldns dynamically,
+ I remembered this immediate_assign-command, I found once in the handbook.
+ Now, the driver first kills all ldn assignments that are set by default
+ on the SCSI-subsystem. After that, it probes on all puns and luns for
+ devices by going through all combinations with immediate_assign and
+ probing for devices, using device_inquiry. The found physical(!) pun,lun
+ structure is stored in get_scsi[][] as device types. This is followed
+ by the assignment of all ldns to existing SCSI-devices. If more ldns
+ than devices are available, they are assigned to non existing pun,lun
+ combinations to satisfy the adapter. With this, the dynamical mapping
+ was possible to implement. (For further info see the text in the
+ source-code and in the description below. Read the description
+ below BEFORE installing this driver on your system!)
+ 3) The LED-display shows on PS/2-95 no longer the ldn, but the SCSI-ID
+ (pun) of the accessed SCSI-device. This is now senseful, because the
+ pun known within the driver is exactly the pun of the physical device
+ and no longer a fake one.
+ 4) The /proc/scsi/ibmmca/<host_no> consists now of the first part, where
+ hit-statistics of ldns is shown and a second part, where the maps of
+ physical and logical SCSI-devices are displayed. This could be very
+ interesting, when one is using more than 15 SCSI-devices in order to
+ follow the dynamical remapping of ldns.
+ - Michael Lang
+ June 26-29 1997: (v2.0b-1)
+ 1) I forgot to switch the local_checking_phase_flag to 1 and back to 0
+ in the dynamical remapping part in ibmmca_queuecommand for the
+ device_exist routine. Sorry.
+ - Michael Lang
+ July 1-13 1997: (v3.0b,c)
+ 1) Merging of the driver-developments of Klaus Kudielka and Michael Lang
+ in order to get a optimum and unified driver-release for the
+ IBM-SCSI-Subsystem-Adapter(s).
+ For people, using the Kernel-release >=2.1.0, module-support should
+ be no problem. For users, running under <2.1.0, module-support may not
+ work, because the methods have changed between 2.0.x and 2.1.x.
+ 2) Added some more effective statistics for /proc-output.
+ 3) Change typecasting at necessary points from (unsigned long) to
+ virt_to_bus().
+ 4) Included #if... at special points to have specific adaption of the
+ driver to kernel 2.0.x and 2.1.x. It should therefore also run with
+ later releases.
+ 5) Magneto-Optical drives and medium-changers are also recognized, now.
+ Therefore, we have a completely gapfree recognition of all SCSI-
+ device-types, that are known by Linux up to kernel 2.1.31.
+ 6) The flag SCSI_IBMMCA_DEV_RESET has been inserted. If it is set within
+ the configuration, each connected SCSI-device will get a reset command
+ during boottime. This can be necessary for some special SCSI-devices.
+ This flag should be included in
+ (See also the new file.)
+ Probable next improvement: bad disk handler.
+ - Michael Lang
+ Sept 14 1997: (v3.0c)
+ 1) Some debugging and speed optimization applied.
+ - Michael Lang
+ Dec 15, 1997
+ -
+ - made the front panel display thingy optional, specified from the
+ command-line via ibmmcascsi=display. Along the lines of the /LED
+ option for the OS/2 driver.
+ - fixed small bug in the LED display that would hang some machines.
+ - reversed ordering of the drives (using the
+ IBMMCA_SCSI_ORDER_STANDARD define). This is necessary for two main
+ reasons:
+ - users who've already installed Linux won't be screwed. Keep
+ in mind that not everyone is a kernel hacker.
+ - be consistent with the BIOS ordering of the drives. In the
+ BIOS, id 6 is C:, id 0 might be D:. With this scheme, they'd be
+ backwards. This confuses the crap out of those heathens who've
+ got a impure Linux installation (which, <wince>, I'm one of).
+ This whole problem arises because IBM is actually non-standard with
+ the id to BIOS mappings. You'll find, in fdomain.c, a similar
+ comment about a few FD BIOS revisions. The Linux (and apparently
+ industry) standard is that C: maps to scsi id (0,0). Let's stick
+ with that standard.
+ - Since this is technically a branch of my own, I changed the
+ version number to 3.0e-cpb.
+ Jan 17, 1998: (v3.0f)
+ 1) Addition of some statistical info for /proc in proc_info.
+ 2) Taking care of the SCSI-assignment problem, dealed by Chris at Dec 15
+ 1997. In fact, IBM is right, concerning the assignment of SCSI-devices
+ to driveletters. It is conform to the ANSI-definition of the SCSI-
+ standard to assign drive C: to SCSI-id 6, because it is the highest
+ hardware priority after the hostadapter (that has still today by
+ default everywhere id 7). Also realtime-operating systems that I use,
+ like LynxOS and OS9, which are quite industrial systems use top-down
+ numbering of the harddisks, that is also starting at id 6. Now, one
+ sits a bit between two chairs. On one hand side, using the define
+ IBMMCA_SCSI_ORDER_STANDARD makes Linux assigning disks conform to
+ the IBM- and ANSI-SCSI-standard and keeps this driver downward
+ compatible to older releases, on the other hand side, people is quite
+ habituated in believing that C: is assigned to (0,0) and much other
+ SCSI-BIOS do so. Therefore, I moved the IBMMCA_SCSI_ORDER_STANDARD
+ define out of the driver and put it into as subitem of
+ 'IBM SCSI support'. A help, added to Documentation/
+ explains the differences between saying 'y' or 'n' to the user, when
+ IBMMCA_SCSI_ORDER_STANDARD prompts, so the ordinary user is enabled to
+ choose the way of assignment, depending on his own situation and gusto.
+ 3) Adapted SCSI_IBMMCA_DEV_RESET to the local naming convention, so it is
+ 4) Optimization of proc_info and its subroutines.
+ 5) Added more in-source-comments and extended the driver description by
+ some explanation about the SCSI-device-assignment problem.
+ - Michael Lang
+ Jan 18, 1998: (v3.0g)
+ 1) Correcting names to be absolutely conform to the later 2.1.x releases.
+ This is necessary for
+ - Michael Lang
+ Jan 18, 1999: (v3.1 MCA-team internal)
+ 1) The multiple hosts structure is accessed from every subroutine, so there
+ is no longer the address of the device structure passed from function
+ to function, but only the hostindex. A call by value, nothing more. This
+ should really be understood by the compiler and the subsystem should get
+ the right values and addresses.
+ 2) The SCSI-subsystem detection was not complete and quite hugely buggy up
+ to now, compared to the technical manual. The interpretation of the pos2
+ register is not as assumed by people before, therefore, I dropped a note
+ in the ibmmca_detect function to show the registers' interpretation.
+ The pos-registers of integrated SCSI-subsystems do not contain any
+ information concerning the IO-port offset, really. Instead, they contain
+ some info about the adapter, the chip, the NVRAM .... The I/O-port is
+ fixed to 0x3540 - 0x3547. There can be more than one adapters in the
+ slots and they get an offset for the I/O area in order to get their own
+ I/O-address area. See chapter 2 for detailed description. At least, the
+ detection should now work right, even on models other than 95. The 95ers
+ came happily around the bug, as their pos2 register contains always 0
+ in the critical area. Reserved bits are not allowed to be interpreted,
+ therefore, IBM is allowed to set those bits as they like and they may
+ really vary between different PS/2 models. So, now, no interpretation
+ of reserved bits - hopefully no trouble here anymore.
+ 3) The command error, which you may get on models 55, 56, 57, 70, 77 and
+ P70 may have been caused by the fact, that adapters of older design do
+ not like sending commands to non-existing SCSI-devices and will react
+ with a command error as a sign of protest. While this error is not
+ present on IBM SCSI Adapter w/cache, it appears on IBM Integrated SCSI
+ Adapters. Therefore, I implemented a workarround to forgive those
+ adapters their protests, but it is marked up in the statisctis, so
+ after a successful boot, you can see in /proc/scsi/ibmmca/<host_number>
+ how often the command errors have been forgiven to the SCSI-subsystem.
+ If the number is bigger than 0, you have a SCSI subsystem of older
+ design, what should no longer matter.
+ 4) ibmmca_getinfo() has been adapted very carefully, so it shows in the
+ slotn file really, what is senseful to be presented.
+ 5) ibmmca_register() has been extended in its parameter list in order to
+ pass the right name of the SCSI-adapter to Linux.
+ - Michael Lang
+ Feb 6, 1999: (v3.1)
+ 1) Finally, after some 3.1Beta-releases, the 3.1 release. Sorry, for
+ the delayed release, but it was not finished with the release of
+ Kernel 2.2.0.
+ - Michael Lang
+ Feb 10, 1999 (v3.1)
+ 1) Added a new commandline parameter called 'bypass' in order to bypass
+ every integrated subsystem SCSI-command consequently in case of
+ troubles.
+ 2) Concatenated read_capacity requests to the harddisks. It gave a lot
+ of troubles with some controllers and after I wanted to apply some
+ extensions, it jumped out in the same situation, on my w/cache, as like
+ on D. Weinehalls' Model 56, having integrated SCSI. This gave me the
+ descissive hint to move the code-part out and declare it global. Now,
+ it seems to work by far much better an more stable. Let us see, what
+ the world thinks of it...
+ 3) By the way, only Sony DAT-drives seem to show density code 0x13. A
+ test with a HP drive gave right results, so the problem is vendor-
+ specific and not a problem of the OS or the driver.
+ - Michael Lang
+ Feb 18, 1999 (v3.1d)
+ 1) The abort command and the reset function have been checked for
+ inconsistencies. From the logical point of thinking, they work
+ at their optimum, now, but as the subsystem does not answer with an
+ interrupt, abort never finishes, sigh...
+ 2) Everything, that is accessed by a busmaster request from the adapter
+ is now declared as global variable, even the return-buffer in the
+ local checking phase. This assures, that no accesses to undefined memory
+ areas are performed.
+ 3) In ibmmca.h, the line unchecked_isa_dma is added with 1 in order to
+ avoid memory-pointers for the areas higher than 16MByte in order to
+ be sure, it also works on 16-Bit Microchannel bus systems.
+ 4) A lot of small things have been found, but nothing that endangered the
+ driver operations. Just it should be more stable, now.
+ - Michael Lang
+ Feb 20, 1999 (v3.1e)
+ 1) I took the warning from the Linux Kernel Hackers Guide serious and
+ checked the cmd->result return value to the done-function very carefully.
+ It is obvious, that the IBM SCSI only delivers the tsb.dev_status, if
+ some error appeared, else it is undefined. Now, this is fixed. Before
+ any SCB command gets queued, the tsb.dev_status is set to 0, so the
+ cmd->result won't screw up Linux higher level drivers.
+ 2) The reset-function has slightly improved. This is still planed for
+ abort. During the abort and the reset function, no interrupts are
+ allowed. This is however quite hard to cope with, so the INT-status
+ register is read. When the interrupt gets queued, one can find its
+ status immediately on that register and is enabled to continue in the
+ reset function. I had no chance to test this really, only in a bogus
+ situation, I got this function running, but the situation was too much
+ worse for Linux :-(, so tests will continue.
+ 3) Buffers got now consistent. No open address mapping, as before and
+ therefore no further troubles with the unassigned memory segmentation
+ faults that scrambled probes on 95XX series and even on 85XX series,
+ when the kernel is done in a not so perfectly fitting way.
+ 4) Spontaneous interrupts from the subsystem, appearing without any
+ command previously queued are answered with a DID_BAD_INTR result.
+ 5) Taken into account ZP Gus' proposals to reverse the SCSI-device
+ scan order. As it does not work on Kernel 2.1.x or 2.2.x, as proposed
+ by him, I implemented it in a slightly derived way, which offers in
+ addition more flexibility.
+ - Michael Lang
+ Apr 23, 2000 (v3.2pre1)
+ 1) During a very long time, I collected a huge amount of bugreports from
+ various people, trying really quite different things on their SCSI-
+ PS/2s. Today, all these bugreports are taken into account and should be
+ mostly solved. The major topics were:
+ - Driver crashes during boottime by no obvious reason.
+ - Driver panics while the midlevel-SCSI-driver is trying to inquire
+ the SCSI-device properties, even though hardware is in perfect state.
+ - Displayed info for the various slot-cards is interpreted wrong.
+ The main reasons for the crashes were two:
+ 1) The commands to check for device information like INQUIRY,
+ to deliver information of up to 255 bytes. Midlevel drivers offer
+ 1024 bytes of space for the answer, but the IBM-SCSI-adapters do
+ not accept this, as they stick quite near to ANSI-SCSI and report
+ a COMMAND_ERROR message which causes the driver to panic. The main
+ problem was located around the INQUIRY command. Now, for all the
+ mentioned commands, the buffersize, sent to the adapter is at
+ maximum 255 which seems to be a quite reasonable solution.
+ TEST_UNIT_READY gets a buffersize of 0 to make sure, that no
+ data is transferred in order to avoid any possible command failure.
+ 2) On unsuccessful TEST_UNIT_READY, the midlevel-driver has to send
+ a REQUEST_SENSE in order to see, where the problem is located. This
+ REQUEST_SENSE may have various length in its answer-buffer. IBM
+ SCSI-subsystems report a command failure, if the returned buffersize
+ is different from the sent buffersize, but this can be supressed by
+ a special bit, which is now done and problems seem to be solved.
+ 2) Code adaption to all kernel-releases. Now, the 3.2 code compiles on
+ 2.0.x, 2.1.x, 2.2.x and 2.3.x kernel releases without any code-changes.
+ 3) Commandline-parameters are recognized again, even under Kernel 2.3.x or
+ higher.
+ - Michael Lang
+ April 27, 2000 (v3.2pre2)
+ 1) Bypassed commands get read by the adapter by one cycle instead of two.
+ This increases SCSI-performance.
+ 2) Synchronous datatransfer is provided for sure to be 5 MHz on older
+ SCSI and 10 MHz on internal F/W SCSI-adapter.
+ 3) New commandline parameters allow to force the adapter to slow down while
+ in synchronous transfer. Could be helpful for very old devices.
+ - Michael Lang
+ June 2, 2000 (v3.2pre5)
+ 1) Added Jim Shorney's contribution to make the activity indicator
+ flashing in addition to the LED-alphanumeric display-panel on
+ models 95A. To be enabled to choose this feature freely, a new
+ commandline parameter is added, called 'activity'.
+ 2) Added the READ_CONTROL bit for test_unit_ready SCSI-command.
+ 3) Added some suppress_exception bits to read_device_capacity and
+ all device_inquiry occurrences in the driver code.
+ 4) Complaints about the various KERNEL_VERSION implementations are
+ taken into account. Every local_LinuxKernelVersion occurrence is
+ now replaced by KERNEL_VERSION, defined in linux/version.h.
+ Corresponding changes were applied to ibmmca.h, too. This was a
+ contribution to all kernel-parts by Philipp Hahn.
+ - Michael Lang
+ July 17, 2000 (v3.2pre8)
+ A long period of collecting bugreports from all corners of the world
+ now lead to the following corrections to the code:
+ 1) SCSI-2 F/W support crashed with a COMMAND ERROR. The reason for this
+ was, that it is possible to disbale Fast-SCSI for the external bus.
+ The feature-control command, where this crash appeared regularly tried
+ to set the maximum speed of 10MHz synchronous transfer speed and that
+ reports a COMMAND ERROR, if external bus Fast-SCSI is disabled. Now,
+ the feature-command probes down from maximum speed until the adapter
+ stops to complain, which is at the same time the maximum possible
+ speed selected in the reference program. So, F/W external can run at
+ 5 MHz (slow-) or 10 MHz (fast-SCSI). During feature probing, the
+ COMMAND ERROR message is used to detect if the adapter does not complain.
+ 2) Up to now, only combined busmode is supported, if you use external
+ SCSI-devices, attached to the F/W-controller. If dual bus is selected,
+ only the internal SCSI-devices get accessed by Linux. For most
+ applications, this should do fine.
+ 3) Wide-SCSI-addressing (16-Bit) is now possible for the internal F/W
+ bus on the F/W adapter. If F/W adapter is detected, the driver
+ automatically uses the extended PUN/LUN <-> LDN mapping tables, which
+ are now new from 3.2pre8. This allows PUNs between 0 and 15 and should
+ provide more fun with the F/W adapter.
+ 4) Several machines use the SCSI: POS registers for internal/undocumented
+ storage of system relevant info. This confused the driver, mainly on
+ models 9595, as it expected no onboard SCSI only, if all POS in
+ the integrated SCSI-area are set to 0x00 or 0xff. Now, the mechanism
+ to check for integrated SCSI is much more restrictive and these problems
+ should be history.
+ - Michael Lang
+ July 18, 2000 (v3.2pre9)
+ This develop rather quickly at the moment. Two major things were still
+ missing in 3.2pre8:
+ 1) The adapter PUN for F/W adapters has 4-bits, while all other adapters
+ have 3-bits. This is now taken into account for F/W.
+ 2) When you select CONFIG_IBMMCA_SCSI_ORDER_STANDARD, you should
+ normally get the inverse probing order of your devices on the SCSI-bus.
+ The ANSI device order gets scrambled in version 3.2pre8!! Now, a new
+ and tested algorithm inverts the device-order on the SCSI-bus and
+ automatically avoids accidental access to whatever SCSI PUN the adapter
+ is set and works with SCSI- and Wide-SCSI-addressing.
+ - Michael Lang
+ July 23, 2000 (v3.2pre10 unpublished)
+ 1) LED panel display supports wide-addressing in ibmmca=display mode.
+ 2) Adapter-information and autoadaption to address-space is done.
+ 3) Auto-probing for maximum synchronous SCSI transfer rate is working.
+ 4) Optimization to some embedded function calls is applied.
+ 5) Added some comment for the user to wait for SCSI-devices being probed.
+ 6) Finished version 3.2 for Kernel 2.4.0. It least, I thought it is but...
+ - Michael Lang
+ July 26, 2000 (v3.2pre11)
+ 1) I passed a horrible weekend getting mad with NMIs on kernel 2.2.14 and
+ a model 9595. Asking around in the community, nobody except of me has
+ seen such errors. Weired, but I am trying to recompile everything on
+ the model 9595. Maybe, as I use a specially modified gcc, that could
+ cause problems. But, it was not the reason. The true background was,
+ that the kernel was compiled for i386 and the 9595 has a 486DX-2.
+ Normally, no troubles should appear, but for this special machine,
+ only the right processor support is working fine!
+ 2) Previous problems with synchronous speed, slowing down from one adapter
+ to the next during probing are corrected. Now, local variables store
+ the synchronous bitmask for every single adapter found on the MCA bus.
+ 3) LED alphanumeric panel support for XX95 systems is now showing some
+ alive rotator during boottime. This makes sense, when no monitor is
+ connected to the system. You can get rid of all display activity, if
+ you do not use any parameter or just ibmmcascsi=activity, for the
+ harddrive activity LED, existant on all PS/2, except models 8595-XXX.
+ If no monitor is available, please use ibmmcascsi=display, which works
+ fine together with the linuxinfo utility for the LED-panel.
+ - Michael Lang
+ July 29, 2000 (v3.2)
+ 1) Submission of this driver for kernel 2.4test-XX and 2.2.17.
+ - Michael Lang
+ December 28, 2000 (v3.2d / v4.0)
+ 1) The interrupt handler had some wrong statement to wait for. This
+ was done due to experimental reasons during 3.2 development but it
+ has shown that this is not stable enough. Going back to wait for the
+ adapter to be not busy is best.
+ 2) Inquiry requests can be shorter than 255 bytes of return buffer. Due
+ to a bug in the ibmmca_queuecommand routine, this buffer was forced
+ to 255 at minimum. If the memory address, this return buffer is pointing
+ to does not offer more space, invalid memory accesses destabilized the
+ kernel.
+ 3) version 4.0 is only valid for kernel 2.4.0 or later. This is necessary
+ to remove old kernel version dependent waste from the driver. 3.2d is
+ only distributed with older kernels but keeps compatibility with older
+ kernel versions. 4.0 and higher versions cannot be used with older
+ kernels anymore!! You must have at least kernel 2.4.0!!
+ 4) The commandline argument 'bypass' and all its functionality got removed
+ in version 4.0. This was never really necessary, as all troubles were
+ based on non-command related reasons up to now, so bypassing commands
+ did not help to avoid any bugs. It is kept in 3.2X for debugging reasons.
+ 5) Dynamical reassignment of ldns was again verified and analyzed to be
+ completely inoperational. This is corrected and should work now.
+ 6) All commands that get sent to the SCSI adapter were verified and
+ completed in such a way, that they are now completely conform to the
+ demands in the technical description of IBM. Main candidates were the
+ be tranferred by bypassing the internal command buffer of the adapter
+ or else the response can be a random result. GET_POS_INFO would be more
+ safe in usage, if one could use the SUPRESS_EXCEPTION_SHORT, but this
+ is not allowed by the technical references of IBM. (Sorry, folks, the
+ model 80 problem is still a task to be solved in a different way.)
+ 7) v3.2d is still hold back for some days for testing, while 4.0 is
+ released.
+ - Michael Lang
+ January 3, 2001 (v4.0a)
+ 1) A lot of complains after the 2.4.0-prerelease kernel came in about
+ the impossibility to compile the driver as a module. This problem is
+ solved. In combination with that problem, some unprecise declaration
+ of the function option_setup() gave some warnings during compilation.
+ This is solved, too by a forward declaration in ibmmca.c.
+ 2) #ifdef argument concerning CONFIG_SCSI_IBMMCA is no longer needed and
+ was entirely removed.
+ 3) Some switch statements got optimized in code, as some minor variables
+ in internal SCSI-command handlers.
+ - Michael Lang
+ 4 To do
+ -------
+ - IBM SCSI-2 F/W external SCSI bus support in separate mode!
+ - It seems that the handling of bad disks is really bad -
+ non-existent, in fact. However, a low-level driver cannot help
+ much, if such things happen.
+ 5 Users' Manual
+ ---------------
+ 5.1 Commandline Parameters
+ --------------------------
+ There exist several features for the IBM SCSI-subsystem driver.
+ The commandline parameter format is:
+ ibmmcascsi=<command1>,<command2>,<command3>,...
+ where commandN can be one of the following:
+ display Owners of a model 95 or other PS/2 systems with an
+ alphanumeric LED display may set this to have their
+ display showing the following output of the 8 digits:
+ ------DA
+ where '-' stays dark, 'D' shows the SCSI-device id
+ and 'A' shows the SCSI hostindex, being currently
+ accessed. During boottime, this will give the message
+ SCSIini*
+ on the LED-panel, where the * represents a rotator,
+ showing the activity during the probing phase of the
+ driver which can take up to two minutes per SCSI-adapter.
+ adisplay This works like display, but gives more optical overview
+ of the activities on the SCSI-bus. The display will have
+ the following output:
+ 6543210A
+ where the numbers 0 to 6 light up at the shown position,
+ when the SCSI-device is accessed. 'A' shows again the SCSI
+ hostindex. If display nor adisplay is set, the internal
+ PS/2 harddisk LED is used for media-activities. So, if
+ you really do not have a system with a LED-display, you
+ should not set display or adisplay. Keep in mind, that
+ display and adisplay can only be used alternatively. It
+ is not recommended to use this option, if you have some
+ wide-addressed devices e.g. at the SCSI-2 F/W adapter in
+ your system. In addition, the usage of the display for
+ other tasks in parallel, like the linuxinfo-utility makes
+ no sense with this option.
+ activity This enables the PS/2 harddisk LED activity indicator.
+ Most PS/2 have no alphanumeric LED display, but some
+ indicator. So you should use this parameter to activate it.
+ If you own model 9595 (Server95), you can have both, the
+ LED panel and the activity indicator in parallel. However,
+ some PS/2s, like the 8595 do not have any harddisk LED
+ activity indicator, which means, that you must use the
+ alphanumeric LED display if you want to monitor SCSI-
+ activity.
+ bypass This is obsolete from driver version 4.0, as the adapters
+ got that far understood, that the selection between
+ integrated and bypassed commands should now work completely
+ correct! For historical reasons, the old description is
+ kept here:
+ This commandline parameter forces the driver never to use
+ SCSI-subsystems' integrated SCSI-command set. Except of
+ the immediate assign, which is of vital importance for
+ every IBM SCSI-subsystem to set its ldns right. Instead,
+ the ordinary ANSI-SCSI-commands are used and passed by the
+ controller to the SCSI-devices, therefore 'bypass'. The
+ effort, done by the subsystem is quite bogus and at a
+ minimum and therefore it should work everywhere. This
+ could maybe solve troubles with old or integrated SCSI-
+ controllers and nasty harddisks. Keep in mind, that using
+ this flag will slow-down SCSI-accesses slightly, as the
+ software generated commands are always slower than the
+ hardware. Non-harddisk devices always get read/write-
+ commands in bypass mode. On the most recent releases of
+ the Linux IBM-SCSI-driver, the bypass command should be
+ no longer a necessary thing, if you are sure about your
+ SCSI-hardware!
+ normal This is the parameter, introduced on the 2.0.x development
+ rail by ZP Gu. This parameter defines the SCSI-device
+ scan order in the new industry standard. This means, that
+ the first SCSI-device is the one with the lowest pun.
+ E.g. harddisk at pun=0 is scanned before harddisk at
+ pun=6, which means, that harddisk at pun=0 gets sda
+ and the one at pun=6 gets sdb.
+ ansi The ANSI-standard for the right scan order, as done by
+ IBM, Microware and Microsoft, scans SCSI-devices starting
+ at the highest pun, which means, that e.g. harddisk at
+ pun=6 gets sda and a harddisk at pun=0 gets sdb. If you
+ like to have the same SCSI-device order, as in DOS, OS-9
+ or OS/2, just use this parameter.
+ fast SCSI-I/O in synchronous mode is done at 5 MHz for IBM-
+ SCSI-devices. SCSI-2 Fast/Wide Adapter/A external bus
+ should then run at 10 MHz if Fast-SCSI is enabled,
+ and at 5 MHz if Fast-SCSI is disabled on the external
+ bus. This is the default setting when nothing is
+ specified here.
+ medium Synchronous rate is at 50% approximately, which means
+ 2.5 MHz for IBM SCSI-adapters and 5.0 MHz for F/W ext.
+ SCSI-bus (when Fast-SCSI speed enabled on external bus).
+ slow The slowest possible synchronous transfer rate is set.
+ This means 1.82 MHz for IBM SCSI-adapters and 2.0 MHz
+ for F/W external bus at Fast-SCSI speed on the external
+ bus.
+ A further option is that you can force the SCSI-driver to accept a SCSI-
+ subsystem at a certain I/O-address with a predefined adapter PUN. This
+ is done by entering
+ commandN = I/O-base
+ commandN+1 = adapter PUN
+ e.g. ibmmcascsi=0x3540,7 will force the driver to detect a SCSI-subsystem
+ at I/O-address 0x3540 with adapter PUN 7. Please only use this method, if
+ the driver does really not recognize your SCSI-adapter! With driver version
+ 3.2, this recognition of various adapters was hugely improved and you
+ should try first to remove your commandline arguments of such type with a
+ newer driver. I bet, it will be recognized correctly. Even multiple and
+ different types of IBM SCSI-adapters should be recognized correctly, too.
+ Use the forced detection method only as last solution!
+ Examples:
+ ibmmcascsi=adisplay
+ This will use the advanced display mode for the model 95 LED alphanumeric
+ display.
+ ibmmcascsi=display,0x3558,7
+ This will activate the default display mode for the model 95 LED display
+ and will force the driver to accept a SCSI-subsystem at I/O-base 0x3558
+ with adapter PUN 7.
+ 5.2 Troubleshooting
+ -------------------
+ The following FAQs should help you to solve some major problems with this
+ driver.
+ Q: "Reset SCSI-devices at boottime" halts the system at boottime, why?
+ A: This is only tested with the IBM SCSI Adapter w/cache. It is not
+ yet prooved to run on other adapters, however you may be lucky.
+ In version 3.1d this has been hugely improved and should work better,
+ now. Normally you really won't need to activate this flag in the
+ kernel configuration, as all post 1989 SCSI-devices should accept
+ the reset-signal, when the computer is switched on. The SCSI-
+ subsystem generates this reset while being initialized. This flag
+ is really reserved for users with very old, very strange or self-made
+ SCSI-devices.
+ Q: Why is the SCSI-order of my drives mirrored to the device-order
+ seen from OS/2 or DOS ?
+ A: It depends on the operating system, if it looks at the devices in
+ ANSI-SCSI-standard (starting from pun 6 and going down to pun 0) or
+ if it just starts at pun 0 and counts up. If you want to be conform
+ with OS/2 and DOS, you have to activate this flag in the kernel
+ configuration or you should set 'ansi' as parameter for the kernel.
+ The parameter 'normal' sets the new industry standard, starting
+ from pun 0, scanning up to pun 6. This allows you to change your
+ opinion still after having already compiled the kernel.
+ Q: Why I cannot find the IBM MCA SCSI support in the config menue?
+ A: You have to activate MCA bus support, first.
+ Q: Where can I find the latest info about this driver?
+ A: See the file MAINTAINERS for the current WWW-address, which offers
+ updates, info and Q/A lists. At this files' origin, the webaddress
+ was:
+ Q: My SCSI-adapter is not recognized by the driver, what can I do?
+ A: Just force it to be recognized by kernel parameters. See section 5.1.
+ If this really happens, do also send e-mail to the maintainer, as
+ forced detection should be never necessary. Forced detection is in
+ principal some flaw of the driver adapter detection and goes into
+ bugreports.
+ Q: The driver screws up, if it starts to probe SCSI-devices, is there
+ some way out of it?
+ A: Yes, that was some recognition problem of the correct SCSI-adapter
+ and its I/O base addresses. Upgrade your driver to the latest release
+ and it should be fine again.
+ Q: I get a message: panic IBM MCA SCSI: command error .... , what can
+ I do against this?
+ A: Previously, I followed the way by ignoring command errors by using
+ ibmmcascsi=forgiveall, but this command no longer exists and is
+ obsolete. If such a problem appears, it is caused by some segmentation
+ fault of the driver, which maps to some unallowed area. The latest
+ version of the driver should be ok, as most bugs have been solved.
+ Q: There are still kernel panics, even after having set
+ ibmmcascsi=forgiveall. Are there other possibilities to prevent
+ such panics?
+ A: No, get just the latest release of the driver and it should work
+ better and better with increasing version number. Forget about this
+ ibmmcascsi=forgiveall, as also ignorecmd are obsolete.!
+ Q: Linux panics or stops without any comment, but it is probable, that my
+ harddisk(s) have bad blocks.
+ A: Sorry, the bad-block handling is still a feeble point of this driver,
+ but is on the schedule for development in the near future.
+ Q: Linux panics while dynamically assigning SCSI-ids or ldns.
+ A: If you disconnect a SCSI-device from the machine, while Linux is up
+ and the driver uses dynamical reassignment of logical device numbers
+ (ldn), it really gets "angry" if it won't find devices, that were still
+ present at boottime and stops Linux.
+ Q: The system does not recover after an abort-command has been generated.
+ A: This is regrettably true, as it is not yet understood, why the
+ SCSI-adapter does really NOT generate any interrupt at the end of
+ the abort-command. As no interrupt is generated, the abort command
+ cannot get finished and the system hangs, sorry, but checks are
+ running to hunt down this problem. If there is a real pending command,
+ the interrupt MUST get generated after abort. In this case, it
+ should finish well.
+ Q: The system gets in bad shape after a SCSI-reset, is this known?
+ A: Yes, as there are a lot of prescriptions (see the Linux Hackers'
+ Guide) what has to be done for reset, we still share the bad shape of
+ the reset functions with all other low level SCSI-drivers.
+ Astonishingly, reset works in most cases quite ok, but the harddisks
+ won't run in synchonous mode anymore after a reset, until you reboot.
+ Q: Why does my XXX w/Cache adapter not use read-prefetch?
+ A: Ok, that is not completely possible. If a cache is present, the
+ adapter tries to use it internally. Explicitly, one can use the cache
+ with a read prefetch command, maybe in future, but this requires
+ some major overhead of SCSI-commands that risks the performance to
+ go down more than it gets improved. Tests with that are running.
+ Q: I have a IBM SCSI-2 Fast/Wide adapter, it boots in some way and hangs.
+ A: Yes, that is understood, as for sure, your SCSI-2 Fast/Wide adapter
+ was in such a case recognized as integrated SCSI-adapter or something
+ else, but not as the correct adapter. As the I/O-ports get assigned
+ wrongly by that reason, the system should crash in most cases. You
+ should upgrade to the latest release of the SCSI-driver. The
+ recommended version is 3.2 or later. Here, the F/W support is in
+ a stable and reliable condition. Wide-addressing is in addition
+ supported.
+ Q: I get a Ooops message and something like "killing interrupt".
+ A: The reason for this is that the IBM SCSI-subsystem only sends a
+ termination status back, if some error appeared. In former releases
+ of the driver, it was not checked, if the termination status block
+ is NULL. From version 3.2, it is taken care of this.
+ Q: I have a F/W adapter and the driver sees my internal SCSI-devices,
+ but ignores the external ones.
+ A: Select combined busmode in the IBM config-program and check for that
+ no SCSI-id on the external devices appears on internal devices.
+ Reboot afterwards. Dual busmode is supported, but works only for the
+ internal bus, yet. External bus is still ignored. Take care for your
+ SCSI-ids. If combined bus-mode is activated, on some adapters,
+ the wide-addressing is not possible, so devices with ids between 8
+ and 15 get ignored by the driver & adapter!
+ Q: I have a 9595 and I get a NMI during heavy SCSI I/O e.g. during fsck.
+ A COMMAND ERROR is reported and characters on the screen are missing.
+ Warm reboot is not possible. Things look like quite weired.
+ A: Check the processor type of your 9595. If you have an 80486 or 486DX-2
+ processor complex on your mainboard and you compiled a kernel that
+ supports 80386 processors, it is possible, that the kernel cannot
+ keep track of the PS/2 interrupt handling and stops on an NMI. Just
+ compile a kernel for the correct processor type of your PS/2 and
+ everything should be fine. This is necessary even if one assumes,
+ that some 80486 system should be downward compatible to 80386
+ software.
+ Q: Some commands hang and interrupts block the machine. After some
+ timeout, the syslog reports that it tries to call abort, but the
+ machine is frozen.
+ A: This can be a busy wait bug in the interrupt handler of driver
+ version 3.2. You should at least upgrade to 3.2c if you use
+ kernel < 2.4.0 and driver version 4.0 if you use kernel 2.4.0 or
+ later (including all test releases).
+ Q: I have a PS/2 model 80 and more than 16 MBytes of RAM. The driver
+ completely refuses to work, reports NMIs, COMMAND ERRORs or other
+ ambiguous stuff. When reducing the RAM size down below 16 MB,
+ everything is running smoothly.
+ A: No real answer, yet. In any case, one should force the kernel to
+ present SCBs only below the 16 MBytes barrier. Maybe this solves the
+ problem. Not yet tried, but guessing that it could work. To get this,
+ set unchecked_isa_dma argument of ibmmca.h from 0 to 1.
+ 5.3 Bugreports
+ --------------
+ If you really find bugs in the sourcecode or the driver will successfully
+ refuse to work on your machine, you should send a bug report to me. The
+ best for this is to follow the instructions on the WWW-page for this
+ driver. Fill out the bug-report form, placed on the WWW-page and ship it,
+ so the bugs can be taken into account with maximum efforts. But, please
+ do not send bug reports about this driver to Linus Torvalds or Leonard
+ Zubkoff, as Linus is burried in E-Mail and Leonard is supervising all
+ SCSI-drivers and won't have the time left to look inside every single
+ driver to fix a bug and especially DO NOT send modified code to Linus
+ Torvalds or Alan J. Cox which has not been checked here!!! They are both
+ quite burried in E-mail (as me, sometimes, too) and one should first check
+ for problems on my local teststand. Recently, I got a lot of
+ bugreports for errors in the ibmmca.c code, which I could not imagine, but
+ a look inside some Linux-distribution showed me quite often some modified
+ code, which did no longer work on most other machines than the one of the
+ modifier. Ok, so now that there is maintenance service available for this
+ driver, please use this address first in order to keep the level of
+ confusion low. Thank you!
+ When you get a SCSI-error message that panics your system, a list of
+ register-entries of the SCSI-subsystem is shown (from Version 3.1d). With
+ this list, it is very easy for the maintainer to localize the problem in
+ the driver or in the configuration of the user. Please write down all the
+ values from this report and send them to the maintainer. This would really
+ help a lot and makes life easier concerning misunderstandings.
+ Use the bug-report form (see 5.4 for its address) to send all the bug-
+ stuff to the maintainer or write e-mail with the values from the table.
+ 5.4 Support WWW-page
+ --------------------
+ The address of the IBM SCSI-subsystem supporting WWW-page is:
+ Here you can find info about the background of this driver, patches,
+ troubleshooting support, news and a bugreport form. Please check that
+ WWW-page regularly for latest hints. If ever this URL changes, please
+ refer to the MAINTAINERS file in order to get the latest address.
+ For the bugreport, please fill out the formular on the corresponding
+ WWW-page. Read the dedicated instructions and write as much as you
+ know about your problem. If you do not like such formulars, please send
+ some e-mail directly, but at least with the same information as required by
+ the formular.
+ If you have extensive bugreports, including Ooops messages and
+ screen-shots, please feel free to send it directly to the address
+ of the maintainer, too. The current address of the maintainer is:
+ Michael Lang <>
+ 6 References
+ ------------
+ IBM Corp., "Update for the PS/2 Hardware Interface Technical Reference,
+ Common Interfaces", Armonk, September 1991, PN 04G3281,
+ (available in the U.S. for $21.75 at 1-800-IBM-PCTB or in Germany for
+ around 40,-DM at "Hallo IBM").
+ IBM Corp., "Personal System/2 Micro Channel SCSI
+ Adapter with Cache Technical Reference", Armonk, March 1990, PN 68X2365.
+ IBM Corp., "Personal System/2 Micro Channel SCSI
+ Adapter Technical Reference", Armonk, March 1990, PN 68X2397.
+ IBM Corp., "SCSI-2 Fast/Wide Adapter/A Technical Reference - Dual Bus",
+ Armonk, March 1994, PN 83G7545.
+ Friedhelm Schmidt, "SCSI-Bus und IDE-Schnittstelle - Moderne Peripherie-
+ Schnittstellen: Hardware, Protokollbeschreibung und Anwendung", 2. Aufl.
+ Addison Wesley, 1996.
+ Michael K. Johnson, "The Linux Kernel Hackers' Guide", Version 0.6, Chapel
+ Hill - North Carolina, 1995
+ Andreas Kaiser, "SCSI TAPE BACKUP for OS/2 2.0", Version 2.12, Stuttgart
+ 1993
+ Helmut Rompel, "IBM Computerwelt GUIDE", What is what bei IBM., Systeme *
+ Programme * Begriffe, IWT-Verlag GmbH - Muenchen, 1988
+ 7 Credits to
+ ------------
+ 7.1 People
+ ----------
+ Klaus Grimm
+ who already a long time ago gave me the old code from the
+ SCSI-driver in order to get it running for some old machine
+ in our institute.
+ Martin Kolinek
+ who wrote the first release of the IBM SCSI-subsystem driver.
+ Chris Beauregard
+ who for a long time maintained MCA-Linux and the SCSI-driver
+ in the beginning. Chris, wherever you are: Cheers to you!
+ Klaus Kudielka
+ with whom in the 2.1.x times, I had a quite fruitful
+ cooperation to get the driver running as a module and to get
+ it running with multiple SCSI-adapters.
+ David Weinehall
+ for his excellent maintenance of the MCA-stuff and the quite
+ detailed bug reports and ideas for this driver (and his
+ patience ;-)).
+ Alan J. Cox
+ for his bugreports and his bold activities in cross-checking
+ the driver-code with his teststand.
+ 7.2 Sponsors & Supporters
+ -------------------------
+ "Hallo IBM",
+ IBM-Deutschland GmbH
+ the service of IBM-Deutschland for customers. Their E-Mail
+ service is unbeatable. Whatever old stuff I asked for, I
+ always got some helpful answers.
+ Karl-Otto Reimers,
+ IBM Klub - Sparte IBM Geschichte, Sindelfingen
+ for sending me a copy of the w/Cache manual from the
+ IBM-Deutschland archives.
+ Harald Staiger
+ for his extensive hardware donations which allows me today
+ still to test the driver in various constellations.
+ Erich Fritscher
+ for his very kind sponsoring.
+ Louis Ohland,
+ Charles Lasitter
+ for support by shipping me an IBM SCSI-2 Fast/Wide manual.
+ In addition, the contribution of various hardware is quite
+ decessive and will make it possible to add FWSR (RAID)
+ adapter support to the driver in the near future! So,
+ complaints about no RAID support won't remain forever.
+ Yes, folks, that is no joke, RAID support is going to rise!
+ Erik Weber
+ for the great deal we made about a model 9595 and the nice
+ surrounding equipment and the cool trip to Mannheim
+ second-hand computer market. In addition, I would like
+ to thank him for his exhaustive SCSI-driver testing on his
+ 95er PS/2 park.
+ Anthony Hogbin
+ for his direct shipment of a SCSI F/W adapter, which allowed
+ me immediately on the first stage to try it on model 8557
+ together with onboard SCSI adapter and some SCSI w/Cache.
+ Andreas Hotz
+ for his support by memory and an IBM SCSI-adapter. Collecting
+ all this together now allows me to try really things with
+ the driver at maximum load and variety on various models in
+ a very quick and efficient way.
+ Peter Jennewein
+ for his model 30, which serves me as part of my teststand
+ and his cool remark about how you make an ordinary diskette
+ drive working and how to connect it to an IBM-diskette port.
+ Johannes Gutenberg-Universitaet, Mainz &
+ Institut fuer Kernphysik, Mainz Microtron (MAMI)
+ for the offered space, the link, placed on the central
+ homepage and the space to store and offer the driver and
+ related material and the free working times, which allow
+ me to answer all your e-mail.
+ 8 Trademarks
+ ------------
+ IBM, PS/2, OS/2, Microchannel are registered trademarks of International
+ Business Machines Corporation
+ MS-DOS is a registered trademark of Microsoft Corporation
+ Microware, OS-9 are registered trademarks of Microware Systems
+ 9 Disclaimer
+ ------------
+ Beside the GNU General Public License and the dependent disclaimers and disclaimers
+ concerning the Linux-kernel in special, this SCSI-driver comes without any
+ warranty. Its functionality is tested as good as possible on certain
+ machines and combinations of computer hardware, which does not exclude,
+ that dataloss or severe damage of hardware is possible while using this
+ part of software on some arbitrary computer hardware or in combination
+ with other software packages. It is highly recommended to make backup
+ copies of your data before using this software. Furthermore, personal
+ injuries by hardware defects, that could be caused by this SCSI-driver are
+ not excluded and it is highly recommended to handle this driver with a
+ maximum of carefulness.
+ This driver supports hardware, produced by International Business Machines
+ Corporation (IBM).
+Michael Lang