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Disappearing sound on Mageia 7 (WORKAROUND)

PostPosted: Mar 7th, '21, 20:09
by mla
As of a few month ago, my fully up-to-date Mageia 7 developed a peculiar problem. From time to time (once every few days) sound would stop working. I soon worked out that reverting to an older version of .config cured the problem. After a long hunt, I've finally found that the trouble is in the file ~/.config/plasmashellrc -- the section

[ScreenConnectors]
0=DP1

occasionally spontaneously changes to

[ScreenConnectors]
0=DP1
1=:0.0

The only cure I can find is to log out, do a console login (or login as root) and modify the file, removing 1=:0.0 line. (Just modifying the file does not work and the system restores the offending line, presumably on logout.)

Any idea anybody what the root cause might be and how to stop it happening?

Re: Disappearing sound

PostPosted: Mar 8th, '21, 00:25
by doktor5000
Some questions for context, how is your monitor connected, and what are the energy saving setting for your monitor ?

Re: Disappearing sound

PostPosted: Mar 8th, '21, 01:21
by mla
Connected by HDMI. The monitor itself has "Smart energy savings: low". The system energy savings are: Dim screen after 5 minutes, Switch off after 10 minutes, Button event handling: When power button pressed, Prompt logout dialogue.

Re: Disappearing sound

PostPosted: Mar 8th, '21, 02:30
by doktor5000
If you disable energy management (so that the monitor stays on all of the time) - does this issue still appear ?

And could it be that "occasionally" coincides with the monitor turning off, so after 10 minutes ?

Re: Disappearing sound

PostPosted: Mar 8th, '21, 13:22
by mla
I'll give it a try, but I doubt that's the problem. It is certainly *not* the case that every monitor time-out results in loss of sound.

BTW, I might as well mention that recently (much more recently than the sound issue) I've been seeing another problem: when instructed to shut down, the system tends to reboot instead. I doubt the two issues are connected because the reboot one is much more recent, so I mention is just in case, for completeness.

Re: Disappearing sound

PostPosted: Mar 8th, '21, 16:07
by mla
Actually, I could be wrong to say that screen time-outs do not always result in sound loss. I have un-checked the time-out option and we'll see what happens.

Re: Disappearing sound

PostPosted: Mar 8th, '21, 20:17
by mla
Mystery deepens. :-(

1. I've set the screen time-out to 1 minute and let it time out a few times. Sound still working. But!...

2. The file .config/plasmashellrc now contains the supposedly offending line 1=:0.0 so why is sound working? (Yeah, I should have checked it wasn't there before experimenting; I didn't.) Let's try logging out and in again...

3. Nope, the line is still there and the sound still works. OK. Let's logout and reboot the system, then login. Sound still working.

On past experience, when sound does stop working, I just edit the file as previously described in order to remove that line and this cures the problem. If I keep a copy of the newly edited file and, when the problem recurs, compare that backup copy and the current version of plasmashellrc, that wretched 1=:0.0 line is the only difference between them.

Maybe the problem has gone away in the last system update? I'll report if sound disappears again -- can be several days.

Re: Disappearing sound

PostPosted: Mar 9th, '21, 23:55
by mla
Developments! Screen time-outs have nothing to do with it. Today I had sound go in the middle of a Steam game -- very annoying! I *really* didn't want to log out, modify plasmashellrc and login again. So on an off chance I used pavucontrol (no -qt on mga7) and discovered exactly the same symptom as happens to me on every login on mga8: audio profile is changed to "Digital Stereo (HDMI) Output + Analog Stereo Input". So I changed it back to "Analog Stereo Duplex" (not tagged as unavailable on mga7!) and sound got immediately restored.

The upshot is (must be!) that fiddling with plasmashellrc is not really relevant, except that it somehow (no idea how or why) results in restoring the correct audio profile setting. So, obviously a closely related problem to the one we have been discussing in https://forums.mageia.org/en/viewtopic.php?f=26&t=13979&p=81977#p81977

Consequently I am marking this thread as WORKAROUND too. The bug has been reported: https://bugs.mageia.org/show_bug.cgi?id=28565 (I know, my typing is terrible -- got a typo in the bug report heading; mortifying!)

Re: Disappearing sound (WORKAROUND)

PostPosted: Mar 10th, '21, 09:53
by morgano
Your typing is very good.
And, you can edit the report heading :)

And thanks for the report!
Please add the info in your post above to it too.
Bug reports should generally be complete without reading forum.

Re: Disappearing sound (WORKAROUND)

PostPosted: Mar 10th, '21, 13:00
by mla
morgano wrote:Your typing is very good.
And, you can edit the report heading :)


I can? Thanks... I'll have to have another look at that screen. Didn't see anything saying "edit"

morgano wrote:Please add the info in your post above to it too.
Bug reports should generally be complete without reading forum.


I agree and I did -- in fact before posting it on this thread. Did I miss something substantive?

Re: Disappearing sound on Mageia 7 (WORKAROUND)

PostPosted: Mar 19th, '21, 11:42
by jiml8
There's always the brute force method; use chattr -i to make the config file immutable. Then whatever is trying to write to it won't be able to.

Of course, this sets you up for a problem in the distant future after you have forgotten that you did this and some update requires this config file be changed, but you can't have everything. Just keep good notes :D

Re: Disappearing sound on Mageia 7 (WORKAROUND)

PostPosted: Mar 19th, '21, 14:10
by mla
jiml8 wrote:There's always the brute force method; use chattr -i to make the config file immutable. Then whatever is trying to write to it won't be able to.

Which config file would that be? I did try making plasmashellrc immutable, but (a) KDE objects to that and (b) the file change turned out to be a red herring anyway.