Hibernation/resume works 100% of the time with snd_hda_intel unloaded, so this appears to be related to ALSA.

I identified all patches that modified the files in sound/pci/hda between 2.6.27 and 2.6.28-rc1.  I checked in 2.6.28-rc1 and reverted them all except for one necessary for the kernel to compile.  Then, I built the kernel and retested and hibernation/resume worked 100% of the time.

Tomorrow I'm going to carry out bisection within these patches (there are only 91 of them, so it shouldn't take a lot of time).

Please run alsa-info.sh with --no-upload option, and attach the generated file.
This will contain detailed codec information.
The script is found in
    http://www.alsa-project.org/alsa-info.sh

Also, try sound git tree for-linus branch
    git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6.git
There are some pending patches that are not yet in the upstream.
Also it'd be helpful to try master branch of sound git tree as well.

Created attachment 19077 [details]
Output of alsa-info.sh

Output of 'alsa-info.sh --no-upload' attached as requested.

(In reply to comment #4)
> Also, try sound git tree for-linus branch
>     git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6.git
> There are some pending patches that are not yet in the upstream.
> Also it'd be helpful to try master branch of sound git tree as well.

Will do, thanks.

Handled-By : Takashi Iwai <tiwai@suse.de>

Comment #2 is wrong, resume from hibernation also fails with all of the shoud/pci/hda patches from between 2.6.27 and 2.6.28-rc1 reverted.

However, resume from hibernation still succeeds 100% of the time with snd_hda_intel unloaded.

I'm now going to follow the advice from comment #4 and try the new patches.

The patches from the for-linus branch do not fix the problem.

The patches from the master branch do not fix it too.

It appears that the breakage was caused by a patch outside of the ALSA tree, but unfortunately quite some pre-2.6.28-rc1 patches break hibernation on this box.

Thanks for checking.  I also don't think that it's from ALSA side because there are little fundamental changes about PM regarding Realtek codecs.  (I guessed it's a Sigmatel/IDT codec.)

The major difference between unloading and suspend is that the driver calls pci_set_power_state(), such as,
    pci_set_power_state(pci, pci_choose_state(pci, state));
Could be this the culprit?

BTW, you can set power_save=2 option to snd-hda-intel.  This will enable automatic power-saving after two seconds.  In your case, make sure that all unnecessary mixer elements are unmuted.  Otherwise it might not be triggered.

I'm mentioning about power_save because this is essentially an in-driver suspend/resume without the core PM, and interested whether this works at all.

(In reply to comment #11)

First of all, it turns out not to be a regression from 2.6.27 (see below).

> Thanks for checking.  I also don't think that it's from ALSA side because
> there are little fundamental changes about PM regarding Realtek codecs.
> (I guessed it's a Sigmatel/IDT codec.)

The chip in the affected box is Intel 82801G (ICH7) (rev 02)

> The major difference between unloading and suspend is that the driver calls
> pci_set_power_state(), such as,
>     pci_set_power_state(pci, pci_choose_state(pci, state));
> Could be this the culprit?

No, I don't think so (BTW, you can change that to
'pci_set_power_state(pci, PCI_D3hot);', because you don't call pci_eanble_wake() anyway; also you don't need to free IRQs on resume).

Now, more info about the bug:
- I can say for certain that 2.6.27-rc6 and all of the later kernels (including current mainline and -stable) are affected.
- So far, I haven't been able to reproduce the breakage with 2.6.27-rc3 (still under stress testing).
- I am unable to reproduce it with snd_hda_intel unloaded with any of the otherwise affected kernels.
- In fact it is rather hard to reproduce.  Sometimes it happens on the first attempt to resume from hibernation, sometimes on the third or even fourth one.
- The symptom is that it doesn't resume.  Sometimes it hangs solid during resume and hard reset is necessary.  Sometimes it hangs during resume, but it can be rebooted with the magic SysRq (no useful debug info, though).  Sometimes, it just powers off immediately after trying to switch to the image kernel.

"also you don't need to free IRQs on resume" -> that should be "on suspend", sorry.

The problem is independent of snd_hda_intel.  Most probably it was introduced by the following commit:

commit 5f17cfce5776c566d64430f543a289e5cfa4538b
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Thu Sep 4 01:33:59 2008 -0700

    PCI: fix pbus_size_mem() resource alignment for CardBus controllers

Not-Handled-By : Takashi Iwai <tiwai@suse.de>
Notify-Also : Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Notify-Also : Jesse Barnes <jbarnes@virtuousgeek.org>
Notify-Also : Andrew Morton <akpm@linux-foundation.org>

References : http://marc.info/?l=linux-kernel&m=122818451003644&w=4
Handled-By : Linus Torvalds <torvalds@linux-foundation.org>
Notify-Also : Frans Pop <elendil@planet.nl>

*** Bug 11545 has been marked as a duplicate of this bug. ***

This appeared to be an old problem with handling suspend-resume of PCI bridges and PCI Express ports.  For this reason, I'm dropping it from the list of regressions introduced between 2.6.26 and 2.6.27.

For completeness, patches fixing the problem for me have been posted in this thread: http://lkml.org/lkml/2008/12/6/69

Rafael,

AFAIK this BR could be closed as it should be fixed with the suspend/resume rework series you did for 2.6.29.

Cheers,
FJP

Yes, it can be closed now, thanks for the ping.