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authorHeiner Kallweit <hkallweit1@gmail.com>2021-06-06 15:55:55 +0200
committerWolfram Sang <wsa@kernel.org>2021-06-20 22:58:58 +0200
commit065b6211a87746e196b56759a70c7851418dd741 (patch)
treef02f40e128b5dafd8df9b6a885e84bc9ad31009b /drivers/i2c
parent009c9aa5be652675a06d5211e1640e02bbb1c33d (diff)
i2c: i801: Ensure that SMBHSTSTS_INUSE_STS is cleared when leaving i801_access
As explained in [0] currently we may leave SMBHSTSTS_INUSE_STS set, thus potentially breaking ACPI/BIOS usage of the SMBUS device. Seems patch [0] needs a little bit more of review effort, therefore I'd suggest to apply a part of it as quick win. Just clearing SMBHSTSTS_INUSE_STS when leaving i801_access() should fix the referenced issue and leaves more time for discussing a more sophisticated locking handling. [0] https://www.spinics.net/lists/linux-i2c/msg51558.html Fixes: 01590f361e94 ("i2c: i801: Instantiate SPD EEPROMs automatically") Suggested-by: Hector Martin <marcan@marcan.st> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Reviewed-by: Hector Martin <marcan@marcan.st> Reviewed-by: Jean Delvare <jdelvare@suse.de> Tested-by: Jean Delvare <jdelvare@suse.de> Signed-off-by: Wolfram Sang <wsa@kernel.org>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/busses/i2c-i801.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index f9e1c2ceaac0..04a1e38f2a6f 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -978,6 +978,9 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr,
}
out:
+ /* Unlock the SMBus device for use by BIOS/ACPI */
+ outb_p(SMBHSTSTS_INUSE_STS, SMBHSTSTS(priv));
+
pm_runtime_mark_last_busy(&priv->pci_dev->dev);
pm_runtime_put_autosuspend(&priv->pci_dev->dev);
mutex_unlock(&priv->acpi_lock);