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i2c: i801: Ensure that SMBHSTSTS_INUSE_STS is cleared when leaving i801_access

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[ 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@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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Heiner Kallweit 2021-06-06 15:55:55 +02:00 committed by Sasha Levin
parent 018d03fcf7
commit 0221a5a4db
1 changed files with 3 additions and 0 deletions
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3
drivers/i2c/busses/i2c-i801.c
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@ -974,6 +974,9 @@ 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);