ALSA: usbaudio: implement USB autosuspend

Devices are autosuspended if no pcm nor midi channel is open
Mixer devices may be opened. This way they are active when
in use to play or record sound, but can be suspended while
users have a mixer application running.

[Small clean-ups using static inline by tiwai]

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Oliver Neukum 2011-03-11 14:51:12 +01:00 • committed by Takashi Iwai
commit 88a8516a21
6 changed files with 118 additions and 22 deletions