Comment 5 for bug 1210470

I expirienced similar problems. https://bugs.gentoo.org/show_bug.cgi?id=506188

pulseaudio hangs when it tryes to access switched off audio device.

How I reproduced the problem:

I started Gnome 3 session with disabled discrete GPU + HDMI audio. Disabled via vgaswitcheroo before session start.
Switched on radeon GPU via vgaswitcheroo.
Stopped pulseaudio daemon and launched it as foreground process with -vvv options.
Launched sound applet from Gnome Control Center and verified that there is an HDMI Audio output device.
Switched off radeon GPU via vgaswitcheroo.
Tried to access switched off HDMI Audio by pressing 'Test Speakers' button.

The outcome is not responding Sound applet and error messages from pulseaudio:

D: [alsa-source-ALC271X Analog] ratelimit.c: 241 events suppressed
D: [alsa-source-ALC271X Analog] memblock.c: Pool full
W: [alsa-source-ALC271X Analog] asyncq.c: q overrun, queuing locally
D: [alsa-source-ALC271X Analog] memblock.c: Pool full
W: [alsa-source-ALC271X Analog] asyncq.c: q overrun, queuing locally
D: [alsa-source-ALC271X Analog] memblock.c: Pool full
W: [alsa-source-ALC271X Analog] asyncq.c: q overrun, queuing locally
D: [alsa-source-ALC271X Analog] memblock.c: Pool full
W: [alsa-source-ALC271X Analog] asyncq.c: q overrun, queuing locallyt
D: [alsa-source-ALC271X Analog] memblock.c: Pool full
W: [alsa-source-ALC271X Analog] asyncq.c: q overrun, queuing locally
D: [alsa-source-ALC271X Analog] memblock.c: Pool full

The pulseaudio process is not reacted to SIGTERM and SIGKILL.