From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Ferenc Wagner <wferi@niif.hu>
Subject: Re: [linux-pm] intermittent suspend problem again
Date: Fri, 30 Oct 2009 19:18:53 +0100
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Cc: linux-pm@lists.linux-foundation.org,
       Jesse Barnes <jbarnes@virtuousgeek.org>,
       Andrew Morton <akpm@linux-foundation.org>, yakui.zhao@intel.com,
       LKML <linux-kernel@vger.kernel.org>,
       ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
       Len Brown <lenb@kernel.org>
References: <87fx93pwv2.fsf@tac.ki.iif.hu> <200910291936.14082.rjw@sisk.pl> <87fx91q1bc.fsf@tac.ki.iif.hu>
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On Thursday 29 October 2009, Ferenc Wagner wrote:
> "Rafael J. Wysocki" <rjw@sisk.pl> writes:
> 
> > On Thursday 29 October 2009, Ferenc Wagner wrote:
> >> "Rafael J. Wysocki" <rjw@sisk.pl> writes:
> >> 
> >>> On Wednesday 28 October 2009, Ferenc Wagner wrote:
> >>> 
> >>>> Something similar to http://bugzilla.kernel.org/show_bug.cgi?id=13894
> >>>> raised its ugly head again, please see my last comments on that bug.
> >>>
> >>> This very well may be a separete bug, so please file a new bugzilla report
> >>> on this and mark it as a regression.
> >> 
> >> Done.
> >
> > Which number is this?
> 
> http://bugzilla.kernel.org/show_bug.cgi?id=14504

Thanks.

> Submitted containing the following paragraph only:

That should be sufficient.

> >>>> 2.6.32-rc5 feels particularly bad, with frequent failures to switch
> >>>> off the machine after "S|" or freezes after "Snapshotting system".
> >>>> The former does not cause much trouble in itself, as the machine can
> >>>> be switched off and resumed all right, but the latter is nasty.
> >>>> Suspend to RAM works all the time.  The issue is not reproducible,
> >>>> unfortunately, and the kernel change happened almost together with a
> >>>> BIOS upgrade.  Yesterday I switched back to 2.6.31 to see whether it
> >>>> still works stably with the new BIOS.  I'll report back my findings in
> >>>> a couple of days.
> >>>
> >>> OK, thanks.
> >>>
> >>> Still, I'm really afraid we won't be able to debug it any further without a
> >>> reproducible test case.
> >> 
> >> I've got another, fully reproducible but nevertheless neglected ACPI
> >> problem, already mentioned in #13894:
> >> https://bugs.freedesktop.org/show_bug.cgi?id=22126.
> >
> > A side note: I'm totally unhappy with _kernel_ bugs being handled at
> > bugs.freedesktop.org without a notice anywhere else.  Even though they are
> > related to the graphics, the kernel developers in general at least deserve the
> > information that the bugs have been reported.
> >
> > In this particulare case, the bug is clearly related to ACPI and linux-acpi
> > should have received a notification about it.
> 
> When the ACPI relation became clear to me, I notified linux-acpi, see
> http://thread.gmane.org/gmane.linux.acpi.devel/42172/focus=42230

OK, thanks.

> >> Well, it's probably far-fetched, but maybe the two are somehow related...
> >
> > Very well may be.
> >
> >> Can't you perhaps suggest a way forward there?  Or some tricks to create a
> >> reproducible test case here?
> >
> > Well, you can test if the problem is reproducible in the "shutdown" mode of
> > hibernation.
> 
> Ok, I'll go back to 2.6.32-rc5 for testing that.  Does that make any
> difference in the "Snapshotting system" phase?

Yes, it does.

> Freezes happen that time, too, before writing out the image.
> 
> >> Btw. my gut feeling is that hibernation is getting slower with each
> >> kernel release.  I didn't measure it, and didn't even care about
> >> comparable initial states... But could anything explain this, or is
> >> it sheer impatience?
> >
> > Which part of it is getting slower?  Saving the image, suspending
> > devices or the entire hibernation overall?
> 
> "Snapshotting system" before saving the image

That may be a result of changing the way in which image memory is reserved.
How much memory is there in your machine?

> and saving the image as well.  If s2disk didn't report funny huge negative
> ratios all the time,

Hmm.  This looks like a bug in s2disk.

> I'd probably have tried to correlate this with the number of
> saved pages or similar...  But anyway, this is a minor nit, it's still
> far from being unbearable.  If only it worked all the time!

It should.

Thanks,
Rafael
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