From: Heiner Kallweit <hkallweit1@xxxxxxxxx> [ Upstream commit 065b6211a87746e196b56759a70c7851418dd741 ] 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@xxxxxxxxx> Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx> Reviewed-by: Hector Martin <marcan@xxxxxxxxx> Reviewed-by: Jean Delvare <jdelvare@xxxxxxx> Tested-by: Jean Delvare <jdelvare@xxxxxxx> Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/i2c/busses/i2c-i801.c | 3 +++ 1 file changed, 3 insertions(+) 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); -- 2.30.2
