[pulseaudio-tickets] [Bug 99241] microphone not working, strange fix

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=99241

--- Comment #2 from Tanu Kaskinen <tanuk at iki.fi> ---
(In reply to mattia.b89 from comment #0)
> I have a Dell XPS 13 (2015) with Broadwell hardware.
> I am on Arch Linux x86_64, latest version of Pulseaudio and pavucontrol.
> 
> When I power on my laptop, microphone is not working.
> In order to enable it I have to use that instructions
> (https://wiki.archlinux.org/index.php/
> Dell_XPS_13_(9343)#Enabling_the_microphone).
> 
> Issue n.1: Why my microphone is not working "automatically" ?

The wiki page says that the issue is fixed in kernel version 4.5.3. It sounds
like the problem is simply a bad default value in the kernel driver. I think
the reason why switching the port in pavucontrol fixes this is that pulseaudio
reads the current Mic state when it first starts up, but when you change the
port, the old Mic state is ignored.

> As you note, there are two ways in order to achieve the goal; the second one
> is using `pavucontrol`, simply switching the two entries in the menu (full
> instructions here again:
> https://wiki.archlinux.org/index.php/
> Dell_XPS_13_(9343)#Enabling_the_microphone)
> 
> Issue n.2: Why I have to switch twice in order to get the working microphone
> ?

I'm not sure what you mean by "twice". The instructions tell you to switch
first to an external mic port, and since you don't have an external mic
connected, the first switch can't possibly make the mic work. The second switch
is needed to enable the internal mic again.

(In reply to mattia.b89 from comment #1)
> Issue n.3: Why are settings not saved automatically across reboot ?

I don't know. Either the volume restoring isn't working in pulseaudio, or
something alters the alsa mixer state during reboot while pulseaudio is running
(if alsa mixer volume changes when pulseaudio is running and pulseaudio didn't
initiate the change, pulseaudio will assume that the user changed the volume
and pulseaudio should remember the new volume).

To check whether pulseaudio's volume restoring works, you can stop pulseaudio,
change the alsa mixer volume and restart pulseaudio without rebooting.
Pulseaudio should return the volume to what it was at the time pulseaudio was
shut down.

To stop pulseaudio:
systemctl --user disable pulseaudio.socket
systemctl --user stop pulseaudio.socket pulseaudio.service

To restart pulseaudio:
systemctl --user enable pulseaudio.socket
systemctl --user start pulseaudio.socket pulseaudio.service

If the volume restoring seems to be working fine when not rebooting, then I may
not be able to help much. You could try disabling the alsa-state and
alsa-restore services if you have them. I don't think they're needed when using
pulseaudio.

sudo systemctl disable alsa-state alsa-restore

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