At Sun, 30 Nov 2008 08:22:49 -0800, Dan Nicholson wrote:
On Sun, Nov 30, 2008 at 1:01 AM, Takashi Iwai tiwai@suse.de wrote:
At Sat, 29 Nov 2008 12:40:02 -0800, Dan Nicholson wrote:
Hi,
Currently, suspending the computer via pm-suspend (as done from HAL), causes the ALSA state to be stored and restored via alsactl. Here's what the hook looks like:
http://cgit.freedesktop.org/pm-utils/tree/pm/sleep.d/65alsa
Is this still necessary on recent kernels? Is there a list of drivers which properly maintain state across suspend/resume? We're trying to cut down on the amount of work done in userspace which slows down suspend cycles.
The all drivers with PM support should have do store/restore the mixer states. For such drivers, calling alsactl is just a waste of time.
Thanks. Which drivers don't have PM support?
Many. Look though the kernel tree codes under sound directory that has no suspend and resume callbacks.
I don't know who introduced it, but maybe it was a workaround...
Yeah, I'm sure it was a workaround, but we're trying to get rid of the unnecessary ones now.
Even for drivers without PM support, alsactl alone is useless. So I suggest you to remove it.
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