Bug 11559

Summary:	2.6.27-rc6: nohz + s2ram = need to press keys to get progress
Product:	Platform Specific/Hardware	Reporter:	Rafael J. Wysocki (rjw)
Component:	i386	Assignee:	Thomas Gleixner (tglx)
Status:	CLOSED CODE_FIX
Severity:	normal	CC:	mingo, pavel, tglx, xhejtman
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	2.6.27-rc6	Subsystem:
Regression:	Yes	Bisected commit-id:
Bug Depends on:
Bug Blocks:	7216, 10482
Attachments:	Broadcast tick fix The real fix Patch that fixes resume on HP nx6325

Description Rafael J. Wysocki 2008-09-12 12:09:51 UTC

Subject    : 2.6.27-rc6: nohz + s2ram = need to press keys to get progress
Submitter  : Pavel Machek <pavel@suse.cz>
Date       : 2008-09-12 8:31
References : http://marc.info/?l=linux-kernel&m=122121384705262&w=4

This entry is being used for tracking a regression from 2.6.26.  Please don't
close it until the problem is fixed in the mainline.

Comment 1 Rafael J. Wysocki 2008-09-14 16:43:00 UTC

Not a regression from 2.6.26, apparently.

References : http://marc.info/?l=linux-kernel&m=122141369710750&w=4

Comment 2 Lukas Hejtmanek 2008-09-15 01:07:47 UTC

I can see this problem as well. I don't see it in 2.6.27-rc5. I have ThinkPad T61.

Comment 3 Pavel Machek 2008-09-15 02:13:51 UTC

> I can see this problem as well. I don't see it in 2.6.27-rc5. I have ThinkPad
> T61.

Hmm, so while 2.6.26 is broken for me, 2.6.27-rc5 works here. So I
guess I have separate problem that breaks 2.6.26 resume, and there's
indeed a regression from 2.6.27-rc5 to rc6.

									Pavel

Comment 4 Lukas Hejtmanek 2008-09-15 07:43:35 UTC

However, Pavel, I see the same symptoms, hitting several times the keyboard makes the resume proceed but the system is 'sleepy' and while not typing, CPUs are loaded by system up to 100% (only one of the two CPUs). No particular process seems to be eating the CPUs.

Comment 5 Jens Axboe 2008-09-16 12:07:53 UTC

Thomas debugged this one, I'll attach the temporary diff and let Thomas himself write up a real patch description :-)

Comment 6 Jens Axboe 2008-09-16 12:08:54 UTC

Created attachment 17811 [details]
Broadcast tick fix

Comment 7 Thomas Gleixner 2008-09-16 15:35:14 UTC

Created attachment 17817 [details]
The real fix

Comment 8 Pavel Machek 2008-09-16 15:49:32 UTC

> Created an attachment (id=17817)
>  --> (http://bugzilla.kernel.org/attachment.cgi?id=17817&action=view)
> The real fix

Your previous patch worked okay for me... will test this one tommorow.

									Pavel

Comment 9 Pavel Machek 2008-09-17 00:19:48 UTC

On Wed 2008-09-17 00:50:50, Pavel Machek wrote:
> 
> > Created an attachment (id=17817)
> >  --> (http://bugzilla.kernel.org/attachment.cgi?id=17817&action=view)
> > The real fix
> 
> Your previous patch worked okay for me... will test this one tommorow.

Tested, and seems to work ok.

Tested-by: Pavel Machek <pavel@suse.cz>
									Pavel

Comment 10 Rafael J. Wysocki 2008-09-19 16:33:01 UTC

(In reply to comment #7)
> Created an attachment (id=17817) [details]
> The real fix

Bad new here.  This patch breaks resume from RAM on my HP nx6325.  Sorry. :-(

Comment 11 Rafael J. Wysocki 2008-09-20 13:52:27 UTC

Created attachment 17917 [details]
Patch that fixes resume on HP nx6325

Of course this also defeats the purpose of the patch at http://bugzilla.kernel.org/attachment.cgi?id=17817&action=edit .
I tried some other things, but none of them worked. :-(

Comment 12 Rafael J. Wysocki 2008-09-21 11:32:48 UTC

After some more debugging I can say that the patch from comment #7 breaks CPU hotplugging on my machine.  More specifically, CPU1 can be offlined, but every attempt to online it causes the box to crash.  I guess that's what breaks resume.

Comment 13 Rafael J. Wysocki 2008-09-21 12:56:41 UTC

Created bug #11611 to follow the issue described in comment #12, since the patch from comment #7 is in the mainline.

Closing this one.