Combined wait for pcm_wait and ctl_wait

[Jaroslav Kysela]

On 07. 06. 22 11:56, Pavel Hofman wrote:
> Hi,
> 
> Please is there any way to wait for nonblocking read/write at min_avail
> (like snd_pcm_wait) AND nonblocking subscribed ctl event (like
> snd_ctl_wait) in a single combined wait? The goal is to react as fast as
> possible to ctls in aloop and audio gadget devices which notify about
> stream stop and start (at new rate/format/channel count) on the other side.
> 
> I guess some wizardry with file descriptors and polling multiple fds
> could do.

Yes, use snd_ctl_poll_descriptors* and snd_pcm_poll_descriptors* functions to 
fetch descriptors and translate poll states returned from poll(). The alsaloop 
utility from alsa-utils may be used as an example.

						Jaroslav

-- 
Jaroslav Kysela <perex at perex.cz>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.