Re: a11y: pulseaudio muted in squeeze by default
On 30.9.2010 11:49, Samuel Thibault wrote:
I think you mentioned that the libao output doesn't have such blocking
issue, Hynek, can you confirm this?
No, using ALSA directly and using ALSA through libao
is still using ALSA, so in the described scenario, it will
still prevent Pulse Audio to start. Even if the user prefers
Pulse in all his configurations, Pulse audio will fail
to start because ALSA will mix in. So fallback is not
possible now.
Furthermore, libao doesn't contain a function to stop
the sound being played, which make it really unsuitable
for Speech Dispatcher :( We were however talking
about trying to extend libao with this functionality and
possibly use it instead of our own audio backends.
This will probably a good enough
reason for enabling libao support as fallback (which debian-release will
have to agree on).
I think the only solution here is either to
1) Do something in ALSA so that clients attached to DMIX
do not actually block Pulse from claiming the soundcard,
then reconnect those DMIX clients through Pulse.
2) Have Speech Dispatcher detach from the audio resource
when it's session becomes inactive. (So that it doesn't prevent
Pulse Audio in an active session to work the soundcard.)
Solution #2 sounds much simpler to me and solves the problem
for all audio backends, not just ALSA vs. Pulse, but requires
changes in Speech Dispatcher, so it won't help us for 0.7.1.
Whether #1 is possible, I don't know, but it's advantage would
be that between ALSA and Pulse, more conflicts would be resolved
than just Speech Dispatcher.
Best regards,
Hynek
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