hardware: 5.1 amplifier usb-audio
up-to-date fedora rawhide (radeonsi mesa driver), up-to-date steam beta client, trine2 game produces scratchy sound and music.
receive voice chat also produces scratchy sound
The steam big picture mode also produces scratchy sound
*** Bug 73209 has been marked as a duplicate of this bug. ***
* in dmesg, when the 5.1 usb-audio card is enabled, I get those non stopping messages:
retire_playback_urb: 993 callbacks suppressed
they stop when I switch off the card in pavuctl
* I compared with a linux kernel 3.10.4 and a previous version of pulseaudio (debian wheezy with alchemist_beta repos):
while playing trine2, no retire_playback_urb messages in dmesg, the sink input (pactl command output) misses the rate parameter in format field.
It seems pulseaudio misses the rate parameter of the sink input and then tries to play a 44100Hz 5.1 stream on a 48000Hz device which creates the retire_playback_urb messages.
found a workaround:
For my usb-audio 5.1 system (Bose companion 5.1), I modified default-fragments and default-fragment-size-msec in /etc/pulse/daemon.conf:
default-fragments = 8 (instead of 4)
default-fragment-size-msec = 5 (instead of 25)
Still have the retire_playback_urb in dmesg though.