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authorBob Moore <robert.moore@intel.com>2016-08-04 16:43:58 +0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2016-08-13 03:09:33 +0200
commit6ea8c546f3655a81f82672f24b66dad6095bdd07 (patch)
treebf874b9510389cde6268d30423c8e9b76f2daa03 /drivers/acpi/acpica/tbfadt.c
parent2af52c2bd20c50e80b121e15cd50a579e364485a (diff)
ACPICA: FADT support cleanup
ACPICA commit 34ccd43af3fd1870fddfac0617dd0ba706963558 Remove all vestiges of the version 2 FADT which never was included in the ACPI specification. This enabled significant cleanup of both the data table compiler and the disassembler. Added many clarification comments to associate each FADT version with the version of the ACPI spec where it was originally defined. Link: https://github.com/acpica/acpica/commit/34ccd43a Signed-off-by: Bob Moore <robert.moore@intel.com> Signed-off-by: Lv Zheng <lv.zheng@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi/acpica/tbfadt.c')
-rw-r--r--drivers/acpi/acpica/tbfadt.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/acpi/acpica/tbfadt.c b/drivers/acpi/acpica/tbfadt.c
index 620806965243..016bcdce64ed 100644
--- a/drivers/acpi/acpica/tbfadt.c
+++ b/drivers/acpi/acpica/tbfadt.c
@@ -476,17 +476,19 @@ static void acpi_tb_convert_fadt(void)
u32 i;
/*
- * For ACPI 1.0 FADTs (revision 1 or 2), ensure that reserved fields which
+ * For ACPI 1.0 FADTs (revision 1), ensure that reserved fields which
* should be zero are indeed zero. This will workaround BIOSs that
* inadvertently place values in these fields.
*
* The ACPI 1.0 reserved fields that will be zeroed are the bytes located
* at offset 45, 55, 95, and the word located at offset 109, 110.
*
- * Note: The FADT revision value is unreliable. Only the length can be
- * trusted.
+ * Note: The FADT revision value is unreliable because of BIOS errors.
+ * The table length is instead used as the final word on the version.
+ *
+ * Note: FADT revision 3 is the ACPI 2.0 version of the FADT.
*/
- if (acpi_gbl_FADT.header.length <= ACPI_FADT_V2_SIZE) {
+ if (acpi_gbl_FADT.header.length <= ACPI_FADT_V3_SIZE) {
acpi_gbl_FADT.preferred_profile = 0;
acpi_gbl_FADT.pstate_control = 0;
acpi_gbl_FADT.cst_control = 0;