Bug 116311

On a Raspberry Pi 2 running Arch ARM, upon updating the kernel to the distro-provided linux-raspberrypi-4.4.7-1 package, running amixer results in the following error:

% amixer
amixer: Mixer attach default error: No such file or directory

I believe this is due to some change in the way the snd-bcm2835 module sets-up /dev/snd which is just a guess I make based on how it worked when I modprobed it under kernel v4.1.21.

Under 4.1.21-1:
% ls -l /dev/snd
total 0
crw-rw---- 1 root audio 116,  1 Feb 22 09:40 seq
crw-rw---- 1 root audio 116, 33 Feb 22 09:40 timer

# modprobe snd-bcm2835

% ls -l /dev/snd
total 0
crw-rw---- 1 root audio 116,  0 Apr 14 16:00 controlC0
crw-rw---- 1 root audio 116, 16 Apr 14 16:00 pcmC0D0p
crw-rw---- 1 root audio 116, 17 Apr 14 16:00 pcmC0D1p
crw-rw---- 1 root audio 116,  1 Feb 22 09:40 seq
crw-rw---- 1 root audio 116, 33 Apr 14 16:00 timer

Under 4.4.7-1:
% ls -l /dev/snd
total 0
crw-rw---- 1 root audio 116,  1 Feb 22 09:40 seq
crw-rw---- 1 root audio 116, 33 Apr 14 16:01 timer

# modprobe snd-bcm2835

% ls -l /dev/snd
total 0
crw-rw---- 1 root audio 116,  1 Feb 22 09:40 seq
crw-rw---- 1 root audio 116, 33 Apr 14 16:01 timer

For the sake of completeness, here is the amixer output under 4.1.21:

Under 4.1.21-1:
% amixer
Simple mixer control 'PCM',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined
  Playback channels: Mono
  Limits: Playback -10239 - 400
  Mono: Playback 0 [96%] [0.00dB] [on]

I am happy to provide any logs to help diagnose further.  Thank you.