Re: [3/5] 2.6.21-rc4: known regressions (v2)

Thomas Meyer
2007-03-25T17:24:56Z

Adrian Bunk schrieb:
> On Sun, Mar 25, 2007 at 01:41:33PM +0200, Thomas Meyer wrote:
>
>> ...
>> The first suspend to disk is ok. The second suspend to disk has a
>> strange behaviour:
>> 1.) write pm image
>> 2.) the system disable the non-boot cpus again (i guess this happens in
>> power_down())
>> 3.) the system doesn't power down.
>> 4.) pressing any key and the system powers down.
>> ...
>>
>
> Is this also present with 2.6.20, or is it a regression?
>
No, this one is not present in 2.6.20 and this error doesn't (head=
317ec6cd00f25d05d153a780bc178c5335f320ee) occur with NO_HZ=n and
HIGH_RES_TIMERS=n

This error is maybe related with this commit:

commit cd05a1f818073a623455a58e756c5b419fc98db9
Author: Thomas Gleixner <tglx@linutronix.de>
Date: Sat Mar 17 00:25:52 2007 +0100

[PATCH] clockevents: Fix suspend/resume to disk hangs

I finally found a dual core box, which survives suspend/resume without
crashing in the middle of nowhere. Sigh, I never figured out from the
code and the bug reports what's going on.

The observed hangs are caused by a stale state transition of the clock
event devices, which keeps the RCU synchronization away from completion,
when the non boot CPU is brought back up.

The suspend/resume in oneshot mode needs the similar care as the
periodic mode during suspend to RAM. My assumption that the state
transitions during the different shutdown/bringups of s2disk would go
through the periodic boot phase and then switch over to highres resp.
nohz mode were simply wrong.

Add the appropriate suspend / resume handling for the non periodic
modes.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>