[patch 06/22] i2c-i801: Fix resume when PEC is used

[Greg KH]

Fix for bug #6395:
Fail to resume on Tecra M2 with ADM1032 and Intel 82801DBM

The BIOS of the Tecra M2 doesn't like it when it has to reboot or
resume after the i2c-i801 driver has left the SMBus in PEC mode.
I have a more complete fix for 2.6.17 but the simple approach of
leaving the SMBus in non-PEC mode after every transaction should do
for -stable. That's what the i2c-i801 driver was doing up to 2.6.15
(inclusive).

Signed-off-by: Jean Delvare <khali@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/i2c/busses/i2c-i801.c |    5 +++++
 1 file changed, 5 insertions(+)

--- linux-2.6.16.9.orig/drivers/i2c/busses/i2c-i801.c
+++ linux-2.6.16.9/drivers/i2c/busses/i2c-i801.c
@@ -478,6 +478,11 @@ static s32 i801_access(struct i2c_adapte
 		ret = i801_transaction();
 	}
 
+	/* Some BIOSes don't like it when PEC is enabled at reboot or resume
+	   time, so we forcibly disable it after every transaction. */
+	if (hwpec)
+		outb_p(0, SMBAUXCTL);
+
 	if(block)
 		return ret;
 	if(ret)

--
-
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