[pulseaudio-discuss] Effects of avail_min in ALSA kernel stack

[pl bossart]

>    I recently submitted two patches for ALSA kernel stack that
> will guarantee wake_ups to happen at each periodic interrupt.
> Currently that is not the case when avail_min is greater than
> period size.

It's unclear to me why you would want to set avail_min to more than a
period and still get a wake-up for each period. avail_min is supposed
to amount to the interval during which which you don't want to be
awaken. Somehow isn't your period duration not well configured?

>  The patch doesn't seem to cause regression but might break
> applications that depend on non-standard use of ALSA API.
>
> Takashi Iwai noted that PulseAudio might complain about the change
> (not that PulseAudio use non-standard methods).

PulseAudio sets avail_min to the equivalent of the sleep time (with
timer-based scheduling) or enables period events with regular
interrupt-based scheduling. In the latter case the value of avail_min
shouldn't matter. Sounds like your patch would have no effect on PA.

- Pierre