Changing ALSA volume during audio playback causes playback to freeze

[benosteen]

To replicate:

sudo modprobe snd_bcm2835
ogg123 /path/to/random/oggfile

In another window:

alsamixer

Adjusting the volume while playing can cause the playing process to stall, if volume changes are made too rapidly (ie up/down key held down).

/var/log/kern.log is filled with these responses:

Apr 18 20:46:42 raspberrypi kernel: vcos: [3270]: bcm2835_audio_set_ctls_chan:483 bcm2835_audio_set_ctls_chan: result=-1
Apr 18 20:46:42 raspberrypi kernel: Failed to set ALSA controls..
Apr 18 20:46:42 raspberrypi kernel: vcos: [3270]: bcm2835_audio_set_ctls_chan:483 bcm2835_audio_set_ctls_chan: result=-1
Apr 18 20:46:42 raspberrypi kernel: Failed to set ALSA controls..
Apr 18 20:46:42 raspberrypi kernel: vcos: [3270]: bcm2835_audio_set_ctls_chan:483 bcm2835_audio_set_ctls_chan: result=-1
Apr 18 20:46:42 raspberrypi kernel: Failed to set ALSA controls..
Apr 18 20:46:42 raspberrypi kernel: vcos: [3270]: bcm2835_audio_set_ctls_chan:483 bcm2835_audio_set_ctls_chan: result=-1
Apr 18 20:46:42 raspberrypi kernel: Failed to set ALSA controls..
Apr 18 20:46:42 raspberrypi kernel: vcos: [3270]: bcm2835_audio_set_ctls_chan:483 bcm2835_audio_set_ctls_chan: result=-1
Apr 18 20:46:42 raspberrypi kernel: Failed to set ALSA controls..

[singpolyma]

Today I ran mpc volume 100 while mpd was playing. This caused a crash of the ALSA driver (dmesg said something about a NULL pointer). I had to pull power because with ALSA crased, I can't reboot (it tried to stop ALSA, which hangs).

[benosteen]

It's a random chance - I think if you change volume at the wrong time during playback (possibly something to do with the large blocking operation it carries out to transfer sound data to the video core memory) then it will stall.

Changing volume multiple times during a playback gives more chance for a hang to occur.

[popcornmix]

There's been a firmware update that could help ALSA issues. Please update and test.

[singpolyma]

Updated to Jun 21 firmware (according to uname -a, I used rpi-update script). Changing volume while MPD is playing (woah! instead of only 3 settings there's now waaayyy too many... I have to hold down the arrows in alsamixer to do anything!) no longer crashes or freezes, but the playback is replaced by a low hissing sound until I stop and start it again.