From c79cfbaccac0ef81ab3e796da1582a83dcef0ff9 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Thu, 20 Apr 2006 02:43:18 -0700 Subject: [PATCH] i2c-i801: Fix resume when PEC is used 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. The most simple fix is to clear the PEC bit after after every transaction. That's what this driver was doing up to 2.6.15 (inclusive). Thanks to Daniele Gaffuri for the very good report. Signed-off-by: Jean Delvare Cc: Greg KH Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/i2c/busses/i2c-i801.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index 8e0f3158215..dfca7493362 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -478,6 +478,11 @@ static s32 i801_access(struct i2c_adapter * adap, u16 addr, 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) -- cgit v1.2.3-18-g5258