[pulseaudio-discuss] No sound in one Debian 10 partition (and a debug script)

[Eduardo Ochs]

Hi all,

I have two Debian 10 partitions in my laptop, one that was a Debian 9
that I "apt-get dist-upgrade"d to Debian 10, and one in which Debian
10 was installed from scratch using an installation pen drive...

In the "dist-upgrade"d partition sound doesn't work and in the other
one it does, so let me call them the "bad partition" and the "good
partition".

I was guessing that the problem was in ALSA, and to test that I wrote
the script below, ran it in both partitions, and compared their
outputs:

  logthis () { echo $*:; eval $* 2>&1; echo; echo; }
  {
    # Debian version
    logthis cat /etc/issue
    logthis cat /etc/debian_version
    logthis cat /etc/os-release
    logthis lsb_release -da
    logthis hostnamectl

    # List devices and PCMs
    logthis aplay -l
    logthis aplay -L

    # Drivers and modules
    logthis "lspci -vvv | grep -A8 Audio"
    logthis "lspci -knn | grep -A2 Audio"

    # Permissions
    logthis groups
    logthis ls -lAF /proc/asound/

    # This partition
    logthis "mount | grep 'on / '"

    # ALSA state
    logthis "rm -f /tmp/o; /usr/sbin/alsactl -f /tmp/o store; cat /tmp/o"

  } | tee ~/oalsa

then I sent a long e-mail to the ALSA mailing list - this one:

  https://www.mail-archive.com/alsa-user@lists.sourceforge.net/msg32698.html

I got two answers. This one, by Kaj Persson, about MANY other sound
bugs in a dist-upgraded Debian 10,

  https://www.mail-archive.com/alsa-user@lists.sourceforge.net/msg32699.html

and another one, very brief, in private - and possibly sent from a
cell phone -, from Patrick May, saying that he thinks that "aplay -l"
gives me "Subdevices: 0/1" in the bad partition and "Subdevices: 1/1"
in the good partition because something - possibly pulseaudio - is
using one of the subdevices, and that I should try "pulseaudio
--kill"...

I tried to test Patrick's suggestion, but I found that when I kill a
pulseaudio process systemd starts a new one, and I spent about two
hours trying to find a clean way to kill pulseaudio without systemd
restarting it... I couldn't find a way, and the details overwhelmed
me, and my brain overheated! Sorry!... =(

If several people are having problems with sound on dist-upgraded
Debian 10s - note that "several" at this moment means "at least two"!
- then I think that it would be great to have a much bigger version of
the script above that would also make pulseaudio report lots of things
about its status. I can start working on that bigger script, but:

  1) *** ALL HINTS AND SUGGESTIONS ARE WELCOME ***,

  2) again: how do I kill pulseaudio? The most urgent thing now is to
     add a block like this to the script:

       logthis my-kill-pulseaudio
       logthis aplay -l
       logthis my-restart-pulseaudio


Thanks in advance!
  Eduardo Ochs
  http://angg.twu.net/
  http://angg.twu.net/emacsconf2019.html
    (^ on "executable notes")