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.
I found this[1] which suggests that adding 'dtparam=audio=on' to /boot/config.txt will remedy this situation which indeed it does... why is it necessary I guess is my question after running under the 4.1.x series without it? 1. https://www.reddit.com/r/RetroPie/comments/3vrxeo/no_sound_from_any_emulator