From: Takashi Iwai <tiwai@suse.de>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: "Alex Xu (Hello71)" <alex_y_xu@yahoo.ca>,
alsa-devel@alsa-project.org, Roy Spliet <nouveau@spliet.org>,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
linux-pm@vger.kernel.org
Subject: Re: Unrecoverable AER error when resuming from RAM (hda regression in 5.7-rc2)
Date: Thu, 23 Apr 2020 09:05:54 +0200 [thread overview]
Message-ID: <s5h368uy94d.wl-tiwai@suse.de> (raw)
In-Reply-To: <20200422232127.GA24666@google.com>
On Thu, 23 Apr 2020 01:21:27 +0200,
Bjorn Helgaas wrote:
>
> On Wed, Apr 22, 2020 at 11:25:04PM +0200, Takashi Iwai wrote:
> > On Wed, 22 Apr 2020 22:50:28 +0200,
> > Bjorn Helgaas wrote:
> > > ...
> > > I feel like this UR issue could be a PCI core issue or maybe some sort
> > > of misuse of PCI power management, but I can't seem to get traction on
> > > it.
> > >
> > > > Then the display freezes and the system basically falls apart (can't
> > > > even sudo reboot -f, need to use magic sysrq).
> > > >
> > > > I bisected this to "ALSA: hda: Skip controller resume if not needed".
> > > > Setting snd_hda_intel.power_save=0 resolves the issue.
> > >
> > > FWIW, the complete citation is c4c8dd6ef807 ("ALSA: hda: Skip
> > > controller resume if not needed"),
> > > https://git.kernel.org/linus/c4c8dd6ef807, which first appeared in
> > > v5.7-rc2.
> >
> > Yes, and I posted the fix patch right now:
> > https://lore.kernel.org/r/20200422203744.26299-1-tiwai@suse.de
> >
> > The possible cause was the tricky resume code that both HD-audio
> > controller (the parent PCI device) and the codec devices used.
> >
> > At least the patch above seems working for the reporter's machine.
> > Now we need a bit more testing before merging, but it looks promising,
> > so far.
>
> Great, I'm glad you figured something out because I sure wasn't
> getting anywhere!
>
> Maybe this is a tangent, but I can't figure out what
> snd_power_change_state() is doing. It *looks* like it's supposed to
> change the PCI power state, but I gave up trying to figure out where
> it actually touches the device.
Not really, it merely updates the internal state field stored in the
sound card object, see in include/sound/core.h:
static inline void snd_power_change_state(struct snd_card *card, unsigned int state)
{
card->power_state = state;
wake_up(&card->power_sleep);
}
The sound API blocks the operation while suspend/resume explicitly
with this card top-level signal.
thanks,
Takashi
prev parent reply other threads:[~2020-04-23 7:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1587494585.7pihgq0z3i.none.ref@localhost>
2020-04-21 19:08 ` Unrecoverable AER error when resuming from RAM (hda regression in 5.7-rc2) Alex Xu (Hello71)
2020-04-21 19:40 ` Takashi Iwai
2020-04-22 20:50 ` Bjorn Helgaas
2020-04-22 21:25 ` Takashi Iwai
2020-04-22 23:21 ` Bjorn Helgaas
2020-04-23 7:05 ` Takashi Iwai [this message]
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