[ARM] default user audio goes to /dev/null

[Alan Tull]

Release: Ubuntu 9.04 on Babbage1

I'm not changing anything from the 9.04 release.

After install, audio is defaulting to /dev/null
The volume control applet's heading says "Volume Control: Playback: Null Output (PulseAudio Mixer)

The problem is that the default user that was created during install isn't a member of the audio group. Same can be said for video.

Default groups after a install for the install user are:
ubuntu(the default user was named ubuntu in my case) adm dialout cdrom plugdev lpadmin admin sambashare

Doing this added my default user "ubuntu" to the audio and video groups to enable audio and video playback.
sudo usermod -a -G audio,video ubuntu

[Oliver Grawert (ogra)]

since the switch to pulseaudio and policykit the audio group is obsolete and not used in ubuntu anymore

sound is routed through the in-session pulseaudio server who talks to the system soundserver process via dbus.
access is controlled by policykit, the group defaults are absolutely right here ...

since our imx51 kernel in 9.04 has no audio support enabled at all, pulse does what it is supposed to do if there is no alsa device and points correctly to its builtin /dev/null audio device so processes and applications sitting on top of pulse can still connect to something and dont break.

[Alan Tull (r80115)]

9.04 has audio support.

This is not a duplicate. the bug 420447 appears to be a bug in the 2.6.30 kernel port. It builds fine in the 2.6.28 kernel and the release 9.04 has sgtl5000 audio built in the kernel. In fact, if I do the group changes I listed above, audio works without rebuilding the kernel.

So audio is there in the kernel and it does not get detected properly. Maybe my methods of fixing it are wrong. But if the group defaults are right, that does not explain why audio did not come up by default on the 9.04 default install.

[Oliver Grawert (ogra)]

well, if you have to use the audio group there is definately something wrong in the alsa device setup, ubuntu does neither use nor support the audio group anymore since 9.04 in its default setup, using it will give you direct device access to devices that will differ from the ones the pulse backend accesses.

it is a bug in the alsa implementation in the kernel, in SGTL5000 itself, or even only a wrong kernel configuration which is supposed to be handled and fixed in bug 420447

while it is nice to know that you have a workaround by enabling the audio group please understand that we are mostly concerned to get the supposed default setup to function bugfree.