linux-kernel - Re: [PATCH 0/1] Fiji GPU audio register timeout when in BACO state

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Date:   Wed, 29 Apr 2020 09:37:41 +0200
From:   Takashi Iwai <tiwai@...e.de>
To:     Nicholas Johnson <nicholas.johnson-opensource@...look.com.au>
Cc:     Alex Deucher <alexdeucher@...il.com>,
        "Zhou, David(ChunMing)" <David1.Zhou@....com>,
        "alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "amd-gfx@...ts.freedesktop.org" <amd-gfx@...ts.freedesktop.org>,
        Takashi Iwai <tiwai@...e.com>, Lukas Wunner <lukas@...ner.de>,
        "Deucher, Alexander" <Alexander.Deucher@....com>,
        "Koenig, Christian" <Christian.Koenig@....com>
Subject: Re: [PATCH 0/1] Fiji GPU audio register timeout when in BACO state

On Tue, 28 Apr 2020 16:48:45 +0200,
Nicholas Johnson wrote:
> 
> > > > >
> > > > > FWIW, I have a fiji board in a desktop system and it worked fine when
> > > > > this code was enabled.
> > > >
> > > > Is the new DC code used for Fiji boards?  IIRC, the audio component
> > > > binding from amdgpu is enabled only for DC, and without the audio
> > > > component binding the runtime PM won't be linked up, hence you can't
> > > > power up GPU from the audio side access automatically.
> > > >
> > > 
> > > Yes, DC is enabled by default for all cards with runtime pm enabled.
> > 
> > OK, thanks, I found that amdgpu got bound via component in the dmesg
> > output, too:
> > 
> > [   21.294927] snd_hda_intel 0000:08:00.1: bound 0000:08:00.0 (ops amdgpu_dm_audio_component_bind_ops [amdgpu])
> > 
> > This is the place soon after amdgpu driver gets initialized.
> > Then we see later another initialization phase:
> > 
> > [   26.904127] rfkill: input handler enabled
> > [   37.264152] [drm] PCIE GART of 1024M enabled (table at 0x000000F400000000).
> > 
> > here shows 10 seconds between them.  Then, it complained something:
> > 
> > 
> > [   37.363287] [drm] UVD initialized successfully.
> > [   37.473340] [drm] VCE initialized successfully.
> > [   37.477942] amdgpu 0000:08:00.0: [drm] Cannot find any crtc or sizes
> 
> The above would be me hitting WindowsKey+P to change screens, but with 
> no DisplayPort attached to Fiji, hence it unable to find crtc.
> 
> > 
> > ... and go further, and hitting HD-audio error:
> > 
> That would be me having attached the DisplayPort and done WindowsKey+P 
> again.
> 
> > [   38.936624] [drm] fb mappable at 0x4B0696000
> > [   38.936626] [drm] vram apper at 0x4B0000000
> > [   38.936626] [drm] size 33177600
> > [   38.936627] [drm] fb depth is 24
> > [   38.936627] [drm]    pitch is 15360
> > [   38.936673] amdgpu 0000:08:00.0: fb1: amdgpudrmfb frame buffer device
> > [   40.092223] snd_hda_intel 0000:08:00.1: azx_get_response timeout, switching to polling mode: last cmd=0x00170500
> > 
> > After this point, HD-audio communication was screwed up.
> > 
> > This lastcmd in the above message is AC_SET_POWER_STATE verb for the
> > root node to D0, so the very first command to power up the codec. 
> > The rest commands are also about the power up of each node, so the
> > whole error indicate that the power up at runtime resume failed.
> > 
> > So, this looks to me as if the device gets runtime-resumed at the bad
> > moment?
> It does. However, this is not going to be easy to pin down.
> 
> I moved from Arch to Ubuntu, and it behaves differently. I cannot 
> trigger the bug in Ubuntu. Plus, it puts the GPUs asleep, even if 
> attached at boot, unlike Arch. I will continue to try to trigger it. But 
> even if this is a problem with the Linux distribution, it should not be 
> able to trigger a kernel mode bug, so we should persist with finding it.

Sure, that's a bug to be fixed.

This made me thinking what happens if we load the HD-audio driver very
late.  Could you try to blacklist snd-hda-intel module, then load it
manually after plugging the DP monitor and activating it?

Also, could you track who called the problematic power-up sequence,
e.g. by adding WARN_ON_ONCE()?

Last but not least, please check /proc/asound/card1/eld#* files (there
are both card0 and card1 or such that contain eld#* files, and one is
for i915 and another for amdgpu) before and after plugging.  This
shows whether the audio connection was recognized or not.


thanks,

Takashi

--- a/sound/hda/hdac_controller.c
+++ b/sound/hda/hdac_controller.c
@@ -224,6 +224,7 @@ void snd_hdac_bus_update_rirb(struct hdac_bus *bus)
 			dev_err_ratelimited(bus->dev,
 				"spurious response %#x:%#x, last cmd=%#08x\n",
 				res, res_ex, bus->last_cmd[addr]);
+			WARN_ON_ONCE(1);
 		}
 	}
 }