Bug 101697

Summary: Sound disappears w/ LG connected with display port
Product: PulseAudio Reporter: cin <florijanh>
Component: daemonAssignee: pulseaudio-bugs
Status: RESOLVED MOVED QA Contact: pulseaudio-bugs
Severity: normal    
Priority: medium CC: lennart
Version: unspecified   
Hardware: Other   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments: verbose_test1
pactl list (when sound works)
pactl list (when sound not works)
pactl list (when sound not works) PROPER

Description cin 2017-07-05 14:02:19 UTC
Created attachment 132449 [details]
verbose_test1

Hello,

i am running archlinux x64 and using gnome. I have a LG 29EA93-P Monitor connected with display port and got the following issue:

The sound disappears very randomly, sometimes when i pause a video and then press play again, sometimes i play several musicvideos in my playlist and then the sound disappears. I think it happens when there is no sound activity in between. 

When the sound is away i have to close the youtube tab or close the application, open the gnome-shell sound settings and click on test speakers left/right then i hear "eft" or "right" (but it should be "Front left/right") afterwards the sound works again.

Recently i figured out that "pulseaudio -k" also helps.

I tried to get some debug information, please look at the attachment. Let me know if i can help solving this! I struggle with this issue since more then a year.

best regards
Florijan
Comment 1 Tanu Kaskinen 2017-07-05 23:12:42 UTC
Can you run "pactl list" when sound is working and attach the output here (as an attachment, not as a comment, because the output is so long)?

From the log I was able to gather that when pulseaudio started, the HDMI/DP card was being used by some other process. Then apparently the other process stopped using the card, and pulseaudio started to probe it, but during the probing again the third HDMI/DP device was busy again. There were three HDMI/DP devices that were not busy, but they were not connected to anything either. (Even if you have just one physical HDMI/DP connector, it's normal to have several devices appearing in alsa, they are just not connected anywhere.)

Try running "lsof /dev/snd/pcm*" when you notice a problem. That command will list all processes that have alsa PCM devices open. If some other program is using the sound card directly, that will cause problems with pulseaudio.
Comment 2 cin 2017-07-06 09:45:16 UTC
thanks i will try lsof next time.

attached you can find the output of pactl list.

the output of "lsof /dev/snd/pcm*" is the same when it not works:
COMMAND   PID USER   FD   TYPE DEVICE SIZE/OFF  NODE NAME
pulseaudi 951  cin  mem    CHR 116,10          11951 /dev/snd/pcmC1D8p
pulseaudi 951  cin   46u   CHR 116,10      0t0 11951 /dev/snd/pcmC1D8p
Comment 3 cin 2017-07-06 09:45:46 UTC
Created attachment 132476 [details]
pactl list (when sound works)
Comment 4 cin 2017-07-06 09:46:10 UTC
Created attachment 132477 [details]
pactl list (when sound not works)
Comment 5 cin 2017-07-06 09:48:38 UTC
Created attachment 132478 [details]
pactl list (when sound not works) PROPER
Comment 6 Tanu Kaskinen 2017-07-06 13:46:44 UTC
The not-working "pactl list" doesn't have any indication of things not working. Based on the initial log, I thought that the HDMI 3 sink would not exist at all, but maybe that "device busy" problem was a red herring.

Does the volume meter on pavucontrol's "Output Devices" tab show activity when you're playing some audio to the HDMI sink while sound is broken? If there's activity, then pulseaudio is successfully writing audio to the sound card.
Comment 7 cin 2017-07-13 19:56:16 UTC
There is activity. What could be the problem? When pavucontrol is opened and the video is running without sound and i do "pulseaudio -k" i can see the message "pulse audio blah is connecting" and then the sound just works. By now i don't close the application anymore i just execute "pulseaudio -k"

I also run Windows 10 on the same machine. There i have no sound problems, so it is not a hardware defect.
Comment 8 Tanu Kaskinen 2017-07-14 19:37:22 UTC
So this happens after no audio has been played for a while? Can you find some exact time threshold after which the bug can be reproduced reliably? If you can find it, then I suggest trying with "aplay -Dhdmi:1,2 some_longish_file.wav". That will play directly to alsa, without pulseaudio being involved. The file should be long enough that you can conclude "yeah, this is definitely not working" while the file is playing. If you can reproduce the bug with plain alsa, then report the bug to the alsa developers: http://alsa-project.org/main/index.php/Bug_Tracking
Comment 9 GitLab Migration User 2018-07-30 09:56:57 UTC
-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/pulseaudio/pulseaudio/issues/135.

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