Commit cd92a17e authored by Linus Torvalds's avatar Linus Torvalds

iTCO_wdt: fix typo when setting TCO_EN bit

The code used '&= 0x00002000' when it tried to set the TCO_EN bit, which
obviously didn't set that bit at all, but instead just reset all the
other bits in the SMI_EN register.

This bug seemingly caused various random behavior, with Frans Pop
reporting that X.org just silently hung at startup and Rafael Wysocki
reports the fan spinning with full speed.

See
	http://lkml.org/lkml/2008/12/3/178
	http://bugzilla.kernel.org/show_bug.cgi?id=12162

The problem seems to have been triggered by "[WATCHDOG] iTCO_wdt :
problem with rebooting on new ICH9 based motherboards" (commit
7cd5b08b), but the bogus code existed
before that too (in the "supermicro_old_pre_stop()" function), it just
apparently never showed up due to different logic.

In that commit the broken code got moved around and now gets executed
much more.
Reported-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
Tested-by: default avatarFrans Pop <elendil@planet.nl>
Cc: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f6f7b52e
...@@ -392,7 +392,7 @@ static int iTCO_wdt_stop(void) ...@@ -392,7 +392,7 @@ static int iTCO_wdt_stop(void)
/* Bit 13: TCO_EN -> 1 = Enables the TCO logic to generate SMI# */ /* Bit 13: TCO_EN -> 1 = Enables the TCO logic to generate SMI# */
val32 = inl(SMI_EN); val32 = inl(SMI_EN);
val32 &= 0x00002000; val32 |= 0x00002000;
outl(val32, SMI_EN); outl(val32, SMI_EN);
/* Set the NO_REBOOT bit to prevent later reboots, just for sure */ /* Set the NO_REBOOT bit to prevent later reboots, just for sure */
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment