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

[Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au>]

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.

Kind regards,
Nicholas Johnson

Nicholas Johnson (1):
  drm/amdgpu/runpm: Disable runpm on Fiji due to audio register timeout

 drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c | 1 +
 1 file changed, 1 insertion(+)

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2.26.2