No Sound Via Line Out

[royleith]

Sometimes Kubuntu boots to no sound via the Line Out port. Everything seems to be fine with apps reporting playback and the Line Out appearing correctly in Configure Audio Devices, but no sound makes it out of the Line Out socket. Selecting HDMI sound produces sound via the screen (which is appallingly bad because of the screen speaker), but switching back to Line Out just brings silence.

Sometimes a reboot or two restores the sound and sometimes it takes the Windows solution of turning it off and on again, sometimes more than once.

I have had similar problems in an earlier release of Kubuntu, but, in that case, the problem was that the wrong interfaces appeared in Audio Devices.

[jlittle]

I've been having a similar problem after resuming my desktop from sleep. I first encountered it a couple of weeks ago. It only happens sometimes.

Now, this fix is specific for the sound being gone on resuming from sleep, but your problem presents very similarly. Firstly, identify the audio device:

$ lspci -vvv | grep Audio
00:1f.3 Audio device: Intel Corporation 100 Series/C230 Series Chipset Family HDAudio Controller (rev 31)
Subsystem: Gigabyte Technology Co., Ltd 100 Series/C230 Series Chipset Family HD Audio Controller
$ ls /sys/bus/pci/devices | grep 00:1f.3
0000:00:1f.3

Then I have to write a "1" to /sys/bus/pci/devices/0000:00:1f.3/remove:

$ echo 1 | sudo tee /sys/bus/pci/devices/0000:00:1f.3/remove
$ echo 1 | sudo tee /sys/bus/pci/rescan

(Naïvely using sudo echo 1 > does not work because the shell does the redirection before sudo is invoked. One can, alternatively, become root first with sudo -i, but I don't like doing that.)
Some users put a sleep in between the remove and the rescan.

Another approach altogether is to change to the pipewire pulseaudio server, see pipewire. Presumably on hirsute we'd install pipewire-pulse; I haven't tried that.

[jlittle]

In that post I wrote parenthetically:

(One can, alternatively, become root first with sudo -i, but I don't like doing that.)

I've just realized a good reason for not using sudo -i, that was very relevant to my post. I get my shell to log every command I give it, and often rely on that logging. When the OP first posted, I tried to look up the commands I'd used, and I couldn't find them. I had to go through by browser history from a week ago to find again the post that gave me that fix. Took ages. Because I'd slackly used sudo -i the commands didn't go in the log.

[royleith]

Thanks for the help. Of course, my problem refuses to reappear. I will try your solution when the problem reappears. I notice that the Hairy Hippo is due to become extinct soon and so the problem may well go forever at the upgrade.

I was interested in your comment about command logging. It's nice to see that sudo commands are not logged. It would be a shame to have a paper trail of one's password in a log file.

[jlittle]

I was interested in your comment about command logging. It's nice to see that sudo commands are not logged.

It's only the command line that's logged, so the sudo password is not. (I've experimented with tmux logging, but it never stuck.)

[royleith]

The fault reappeared - Hooray... no, Boo!

I tried your recipe twice. The device dutifully disappeared and then reappeared on a rescan. However, the Line Out sound was not restored. I will continue with reboots until the time comes for an upgrade to 21.20. Thanks for the suggestion, though.