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Re: Audio - Dummy Output, except for root




On Mon 25 Jun 2018 at 09:58:29 -0500, Kent West wrote:

> I recently dist-upgraded my Buster/Sid box, and lost:
>  - networking temporarily (got it back, but not exactly sure how)
>  -video (black screen; no obvious local terminal response, but could ssh
> in; it's an NVidia bug apparently, worked around with
> "slab_common.usercopy_fallback=y" added to kernel parameters at start-up)
>  - audio as a normal user.
> 
> So I've fixed the first two issues, but still have no audio when I log into
> X as a normal user (or at least as my normal user; now that I think about
> it, I'll try as a different normal user as soon as I get this email sent
> off).
> 
> In both X11/Cinnamon and X11/Plasma Desktop, the audio button on the panel
> shows "Dummy Output" as the audio device when I log into X as my normal
> user. I added my user to the "audio" group and logged out/in and tried
> again; no change.
> 
> I then Ctrl-Alt-F1'd to TT1, logged in as root, "systemctl stop sddm", and
> "startx &" as root, and the DM was a simpler DM (maybe XFCE? maybe LXDE? it
> wasn't obvious, at least to me), and there was not volume control on any
> panel, so I just fired up Audacity and played a .m4v file, and audio worked
> successfully.
> 
> So audio works for root, but not for my normal user (even after being added
> to the "audio" group).
>
> Any ideas/suggestions?

A user being in the audio group is made redundant by systemd installing
udev rules (/lib/udev/rules.d/70-uaccess.rules) and systemd-logind adding
a locally loggedin user to the ACLs for the corresponding devices.

brian@desktop:~$ ls -l /dev/snd/*
crw-rw----+ 1 root audio 116,  2 Apr 22 14:21 /dev/snd/controlC0
crw-rw----+ 1 root audio 116,  4 May 26 10:40 /dev/snd/pcmC0D0c
crw-rw----+ 1 root audio 116,  3 Jun 24 23:21 /dev/snd/pcmC0D0p
crw-rw----+ 1 root audio 116,  6 Apr 22 14:21 /dev/snd/pcmC0D1c
crw-rw----+ 1 root audio 116,  5 Apr 22 14:21 /dev/snd/pcmC0D1p
crw-rw----+ 1 root audio 116,  1 Apr 22 14:21 /dev/snd/seq
crw-rw----+ 1 root audio 116, 33 Apr 22 14:21 /dev/snd/timer

brian@desktop:~$ getfacl /dev/snd/controlC0
getfacl: Removing leading '/' from absolute path names
# file: dev/snd/controlC0
# owner: root
# group: audio
user::rw-
user:brian:rw-
group::rw-
mask::rw-
other::---

-- 
Brian.