On Thu, Apr 30, 2020 at 07:01:08PM +0200, Takashi Iwai wrote: > On Thu, 30 Apr 2020 18:52:20 +0200, > Nicholas Johnson wrote: > > > > On Thu, Apr 30, 2020 at 05:14:56PM +0200, Takashi Iwai wrote: > > > On Wed, 29 Apr 2020 18:19:57 +0200, > > > Alex Deucher wrote: > > > > > > > > On Wed, Apr 29, 2020 at 12:05 PM Takashi Iwai <tiwai@xxxxxxx> wrote: > > > > > Well, but the code path there is the runtime PM resume of the audio > > > > > device and it means that GPU must have been runtime-resumed again > > > > > beforehand via the device link. So, it should have worked from the > > > > > beginning but in reality not -- that is, apparently some inconsistency > > > > > is found in the initial attempt of the runtime resume... > > > > > > > > Yeah, it should be covered, but I wonder if there is something in the > > > > ELD update sequence that needs to call pm_runtime_get_sync()? The ELD > > > > sequence on AMD GPUs doesn't work the same as on other vendors. The > > > > GPU driver has a backdoor into the HDA device's verbs to set update > > > > the audio state rather than doing it via an ELD buffer update. We > > > > still update the ELD buffer for consistency. Maybe when the GPU > > > > driver sets the audio state at monitor detection time that triggers an > > > > interrupt or something on the HDA side which races with the CPU and > > > > the power down of the GPU. That still seems unlikely though since the > > > > runtime pm on the GPU side defaults to a 5 second suspend timer. > > > > > > I'm not sure whether it's the race between runtime suspend of GPU vs > > > runtime resume of audio. My wild guess is rather that it's the timing > > > GPU notifies to the audio; then the audio driver notifies to > > > user-space and user-space opens the stream, which in turn invokes the > > > runtime resume of GPU. But in GPU side, it's still under processing, > > > so it proceeds before the GPU finishes its initialization job. > > > > > > Nicholas, could you try the patch below and see whether the problem > > > still appears? The patch artificially delays the notification and ELD > > > update for 300msec. If this works, it means the timing problem. > > The bug still occurred after applying the patch. > > > > But you were absolutely correct - it just needed to be increased to > > 3000ms - then the bug stopped. > > Interesting. 3 seconds are too long, but I guess 1 second would work > as well? 1000ms indeed worked as well. > > In anyway, the success with a long delay means that the sound setup > after the full runtime resume of GPU seems working. > > > Now the question is, what do we do now that we know this? > > > > Also, are you still interested in the contents of the ELD# files? I can > > dump them all into a file at some specific moment in time which you > > request, if needed. > > Yes, please take the snapshot before plugging, right after plugging > and right after enabling. I'm not sure whether your monitor supports > the audio, and ELD contents should show that, at least. The monitor supports the audio. There is 3.5mm audio out jack. No inbuilt speakers, although Samsung did sell a sound bar to suit it. The sound bar, which I do not own, presumably attaches via 3.5mm jack. I am not sure if by plugging, you mean hot-adding Thunderbolt GPU or plugging the monitor to the GPU, so I have covered extra cases to be sure. I have taken the eld# files with the 1000ms patch applied, so the error is not triggered. #### Before hot-adding the Thunderbolt GPU: /proc/asound/card1 not present #### #### After hot-adding the GPU with no monitor attached: /proc/asound/card1 contains: eld#0.0 eld#0.1 eld#0.2 eld#0.3 eld#0.4 eld#0.5 All of the above have the same contents: monitor_present 0 eld_valid 0 #### #### Monitor attached to Fiji GPU but not enabled: Same as above #### #### Monitor enabled: All files with same contents except for eld#0.1 which looks like: monitor_present 1 eld_valid 1 monitor_name U32E850 connection_type DisplayPort eld_version [0x2] CEA-861D or below edid_version [0x3] CEA-861-B, C or D manufacture_id 0x2d4c product_id 0xce3 port_id 0x0 support_hdcp 0 support_ai 0 audio_sync_delay 0 speakers [0x1] FL/FR sad_count 1 sad0_coding_type [0x1] LPCM sad0_channels 2 sad0_rates [0xe0] 32000 44100 48000 sad0_bits [0xe0000] 16 20 24 #### Cheers. Regards, Nicholas. > > > thanks, > > Takashi
