Bug#657317: rtkit: pulseaudio looses SCHED_RT when suspending the machine

[Frederik Himpe]

Package: rtkit
Version: 0.10-2
Severity: normal

I noticed sound on my system was constantly stuttering, even when the machine
was not highly loaded. With the help of people on
irc://irc.freenode.org/#pulseaudio, we found out that pulseaudio was not
running with SCHED_RT anymore, even though rtkit-daemon was running. Killing
and restarting pulseaudio fixed the problem.

Apparently the loss of SCHED_RT is caused by suspending the machine:

12:24 < ohsix> heftig: how did you come to find out about this suspend thing
12:25 < ohsix> pulse has a lifecycle change around suspend, it would be easy
for it to ask for rt again when it brings the sinks back up
12:26 < heftig> ohsix: just noticed it today
12:26 < heftig> logs contain demotes by rtkit whenever i suspend
12:26 < ohsix> rtkit could listen to dbus and just promote the threads again
later
12:26 < ohsix> highly interesting
12:26 < |Frederik> Interesting. Is there some bug ticket already I can follow?
12:27 < heftig> Jan 24 10:32:31 shine kernel: sd 0:0:0:0: [sda] Stopping disk
12:27 < heftig> Jan 24 10:32:31 shine kernel: ehci_hcd 0000:00:1d.0: PCI INT A
disabled
12:27 < heftig> Jan 24 10:32:31 shine kernel: ehci_hcd 0000:00:1a.0: PCI INT A
disabled
12:27 < heftig> Jan 24 10:32:31 shine rtkit-daemon[374]: The canary thread is
apparently starving. Taking action.
12:28 < ohsix> could have a different test for discontinuity in the canary
thread too
12:28 < ohsix> that's one of those fun things to overlook




-- System Information:
Debian Release: wheezy/sid
  APT prefers testing
  APT policy: (300, 'testing'), (200, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 3.1.0-1-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_GB.utf8, LC_CTYPE=en_GB.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages rtkit depends on:
ii  adduser      3.113
ii  libc6        2.13-24
ii  libcap2      1:2.22-1
ii  libdbus-1-3  1.4.16-1

rtkit recommends no packages.

rtkit suggests no packages.

-- no debconf information