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

[Takashi Iwai]

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