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

[Alex Deucher]

On Mon, Apr 27, 2020 at 2:07 PM Nicholas Johnson
<nicholas.johnson-opensource@xxxxxxxxxxxxxx> wrote:
>
> On Mon, Apr 27, 2020 at 05:15:55PM +0200, Takashi Iwai wrote:
> > On Mon, 27 Apr 2020 16:22:21 +0200,
> > Deucher, Alexander wrote:
> > >
> > > [AMD Public Use]
> > >
> > > > -----Original Message-----
> > > > From: Nicholas Johnson <nicholas.johnson-opensource@xxxxxxxxxxxxxx>
> > > > Sent: Sunday, April 26, 2020 12:02 PM
> > > > To: linux-kernel@xxxxxxxxxxxxxxx
> > > > Cc: Deucher, Alexander <Alexander.Deucher@xxxxxxx>; Koenig, Christian
> > > > <Christian.Koenig@xxxxxxx>; Zhou, David(ChunMing)
> > > > <David1.Zhou@xxxxxxx>; Nicholas Johnson <nicholas.johnson-
> > > > opensource@xxxxxxxxxxxxxx>
> > > > Subject: [PATCH 0/1] Fiji GPU audio register timeout when in BACO state
> > > >
> > > > Hi all,
> > > >
> > > > Since Linux v5.7-rc1 / commit 4fdda2e66de0 ("drm/amdgpu/runpm: enable
> > > > runpm on baco capable VI+ asics"), my AMD R9 Nano has been using runpm /
> > > > BACO. You can tell visually when it sleeps, because the fan on the graphics
> > > > card is switched off to save power. It did not spin down the fan in v5.6.x.
> > > >
> > > > This is great (I love it), except that when it is sleeping, the PCIe audio function
> > > > of the GPU has issues if anything tries to access it. You get dmesg errors such
> > > > as these:
> > > >
> > > > snd_hda_intel 0000:08:00.1: spurious response 0x0:0x0, last cmd=0x170500
> > > > snd_hda_intel 0000:08:00.1: azx_get_response timeout, switching to polling
> > > > mode: last cmd=0x001f0500 snd_hda_intel 0000:08:00.1: No response from
> > > > codec, disabling MSI: last cmd=0x001f0500 snd_hda_intel 0000:08:00.1: No
> > > > response from codec, resetting bus: last cmd=0x001f0500
> > > > snd_hda_codec_hdmi hdaudioC1D0: Unable to sync register 0x2f0d00. -11
> > > >
> > > > The above is with the Fiji XT GPU at 0000:08:00.0 in a Thunderbolt enclosure
> > > > (not that Thunderbolt should affect it, but I feel I should mention it just in
> > > > case). I dropped a lot of duplicate dmesg lines, as some of them repeated a
> > > > lot of times before the driver gave up.
> > > >
> > > > I offer this patch to disable runpm for Fiji while a fix is found, if you decide
> > > > that is the best approach. Regardless, I will gladly test any patches you come
> > > > up with instead and confirm that the above issue has been fixed.
> > > >
> > > > I cannot tell if any other GPUs are affected. The only other cards to which I
> > > > have access are a couple of AMD R9 280X (Tahiti XT), which use radeon driver
> > > > instead of amdgpu driver.
> > >
> > > Adding a few more people.  Do you know what is accessing the audio?  The audio should have a dependency on the GPU device.  The GPU won't enter runtime pm until the audio has entered runtime pm and vice versa on resume. Please attach a copy of your dmesg output and lspci output.
>
> pci 0000:08:00.1: D0 power state depends on 0000:08:00.0
> The above must be the dependency of which you speak from dmesg.
>
> Accessing the audio? I did not have a single method for triggering it.
> Sometimes it happened on shutdown. Sometimes when restarting gdm.
> Sometimes when playing with audio settings in Cinnamon Desktop. But most
> often when changing displays. It might have something to do with the
> audio device associated with a monitor being created when the monitor is
> found. If an audio device is created, then pulseaudio might touch it.
> Sorry, this is a very verbose "not quite sure".
>
> To trigger the bug, this time I did the following:
>
> 1. Boot laptop without Fiji and log in
>
> 2. Attach Fiji via Thunderbolt (no displays attached to Fiji) and
> approve Thunderbolt device
>
> 3. Log in again because the session gets killed when GPU is hot-added
>
> 4. Wait for Fiji to fall asleep (fan stops)
>
> 5. Open "dmesg -w" on laptop display
>
> 6. Attach display to DisplayPort on Fiji (it should still stay asleep)
>
> 7. Do WindowsKey+P to activate external display. The error appears in
> dmesg window that instant.
>
> Could it be a race condition when waking the card up?
>
> I cannot get the graphics card fan to spin down if the Thunderbolt
> enclosure is attached at boot time. It only does it if hot-added.
>
> If you think it will help, I can take out the Fiji and put it in a test
> rig and try to replicate the issue without Thunderbolt, but it looks
> like it will not spin the fan down if Fiji is attached at boot time.
>
> Question, why would the fan not spin down if Fiji is attached at boot
> time, and how would one make the said fan turn off? Aside from being
> useful for pinning down the audio register issue, I would like to make
> sure the power savings are realised whenever the GPU is not being used.

Presumably something is using the device.  Maybe a framebuffer console
or X?  Or maybe the something like tlp has disabled runtime pm on your
device?  You can see the current status by reading the files in
/sys/class/drm/cardX/device/power/ .  Replace cardX with card0, card1,
etc. depending on which device is the radeon card.

FWIW, I have a fiji board in a desktop system and it worked fine when
this code was enabled.

Alex

>
> >
> > Also, please retest with the fresh 5.7-rc3.  There was a known
> > regression regarding HD-audio PM in 5.7-rc1/rc2, and it's been fixed
> > there (commit 8d6762af302d).
> Linux v5.7-rc3 still has the same problem, unfortunately.
>
> The dmesg is attached.
>
> Thanks for your replies. Kind regards,
> Nicholas
>
> >
> >
> > thanks,
> >
> > Takashi
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