[alsa-devel] kernel oops related to the new HDA audio handling for DP MST

[Takashi Iwai]

On Wed, 27 Nov 2019 19:52:37 +0100,
Michał Matysiak wrote:
> 
> On Wed, Nov 27, 2019 at 06:00:17PM +0100, Takashi Iwai wrote:
> > On Wed, 27 Nov 2019 16:57:04 +0100,
> > Takashi Iwai wrote:
> > > 
> > > On Wed, 27 Nov 2019 16:46:00 +0100,
> > > Hans de Goede wrote:
> > > > 
> > > > Hi Takashi,
> > > > 
> > > > On 27-11-2019 15:39, Takashi Iwai wrote:
> > > > > On Wed, 27 Nov 2019 15:26:37 +0100,
> > > > > Michał Matysiak wrote:
> > > > >>
> > > > >> Hi
> > > > >>
> > > > >> Recently I've encountered this error and as Hans de Goede's request I'm
> > > > >> reporting this back to you. This happens while booting my laptop
> > > > >> connected to docking station and without using one.
> > > > >>
> > > > >> kernel: WARNING: CPU: 1 PID: 330 at sound/hda/hdac_component.c:290 snd_hdac_acomp_init+0xde/0x130 [snd_hda_core]
> > > > >> There are 2 more "cut here", but they're almost identical so I've only
> > > > >> included one in this email.
> > > > >>
> > > > >> Don't know what will be valuable to you, but I'm willing to help test
> > > > >> this and do what I'm told. So, how can I help?
> > > > >>
> > > > >> More info about this particular kernel and issue, that led to this is at:
> > > > >> https://bugzilla.redhat.com/show_bug.cgi?id=1757891
> > > > >>
> > > > >> dmesg output:
> > > > >>
> > > > >> Nov 26 18:05:45 kernel: microcode: microcode updated early to revision 0x2f, date = 2019-02-17
> > > > >> Nov 26 18:05:45 kernel: Linux version 5.4.0-0.rc8.git0.1.rhbz1757891.fc31.x86_64 (mockbuild at buildhw-10.phx2.fedoraproject.org) (gcc version 9.2.1 20190827 (Red Hat 9.2.1-1) (GCC)) #1 SMP Wed Nov 20 14:50:34 UTC 2019
> > > > >> Nov 26 18:05:45 kernel: Command line: BOOT_IMAGE=(hd0,gpt2)/vmlinuz-5.4.0-0.rc8.git0.1.rhbz1757891.fc31.x86_64 root=/dev/mapper/fedora-root ro resume=/dev/mapper/fedora-swap rd.lvm.lv=fedora/root rd.luks.uuid=luks-efd8b438-8f56-405a-8cea-88f83ca38d2b rd.lvm.lv=fedora/swap rhgb quiet
> > > > >> ...
> > > > >> ...
> > > > >> ...
> > > > >> Nov 26 18:06:16 kernel: ------------[ cut here ]------------
> > > > >> Nov 26 18:06:16 kernel: WARNING: CPU: 0 PID: 461 at sound/hda/hdac_component.c:290 snd_hdac_acomp_init+0xde/0x130 [snd_hda_core]
> > > > >
> > > > > This should have been already fixed by the recent commit
> > > > > 5a858e79c911330678b5a9be91a24830e94a0dc9
> > > > >      ALSA: hda - Disable audio component for legacy Nvidia HDMI codecs
> > > > > which is already included in Linus tree.  Please check it.
> > > > 
> > > > Thanks, I've started a scratch kernel build with the relevant patches added,
> > > > for the Fedora users hitting this to test.
> > > > 
> > > > The reason they started looking into their dmesg is that their nvidia GPU (hybrid gfx setup)
> > > > will no longer suspend with recent kernels, this is with a 5.4 kernel which already has the
> > > > 
> > > > "ALSA: hda - Force runtime PM on Nvidia HDMI codecs"
> > > > 
> > > > Fix and for good measure I've already given them a test kernel with the:
> > > > "ALSA: hda: Allow HDA to be runtime suspended when dGPU is not bound to a drive"
> > > > 
> > > > patch added. But looking at the fix for the oops I'm not sure if fixing
> > > > the oops is also going to fix the issue with the dGPU no longer suspending?
> > > 
> > > I guess it's irrelevant with that problem, as this kernel warning (not
> > > really an Oops) is just about skipping the multiple audio component
> > > registration.  And the audio component isn't used in nouveau side on
> > > 5.4.x at all, and it's just a placeholder.  But who knows the black
> > > magic behind the scene :)
> > 
> > ... and if this still doesn't fix the problem, please check the
> > runtime PM state of all HD-audio codec devices and HD-audio controller
> > device.  Do all show the runtime-suspended but the power consumption
> > is high?  Or is some device blocked?
> > 
> > Basically the audio controller corresponding to the dGPU should have
> > chip->bus.keep_power = 0, which allows the runtime PM.  This flag is
> > cleared at azx_vx_gpu_bound() only for the dGPU.  For the primary GPU,
> > we need to keep the link power unless the notification is done via the
> > audio component (like i915 or amdgpu).  I already submitted a patch to
> > enable the audio component for nouveau in the past, but it's ignored,
> > so far.
> > 
> > 
> > thanks,
> > 
> > Takashi
> 
> Hi Takashi
> 
> On linux-next-20191127 warning indeed disappeared. Thanks!
> 
> Rest of problems did not. This is my output from alsa-info.sh
> http://alsa-project.org/db/?f=91bb789a01f9eed92d0534fe8951619312b355da
> Don't know if it's helpful, so I'll leave it here. Power consumption is
> high, because runtime-suspended is not enabled/active (and cannot be
> forced) without removing nvidia's audio.

What if you pass power_save=1 to snd-hda-intel option?

  echo -n 1 > /sys/module/snd_hda_intel/parameters/power_save

This should enable the runtime PM on all HD-audio stuff.  You can
adjust via runtime sysfs entries for each device, while the above is a
one-shot change.

This isn't a solution, but let's see whether the runtime PM itself
works or not.


Takashi