[alsa-devel] hw_ptr accuracy with intel8x0 -> PulseAudio issue

[pl bossart]

> 2) why PA use  snd_pcm_hw_params_get_buffer_size_max() instead of
> snd_pcm_hw_params_get_buffer_size() after snd_pcm_hw_params() ?

Precisely to use the maximum preallocated buffer size.

> I: module-alsa-sink.c: Using 2 fragments of size 4096 bytes, buffer time is
> 46.44ms
> D: alsa-util.c:   buffer_size  : 2048
> D: alsa-util.c:   period_size  : 1024

With small buffers like this, I don't see the point of the timer-based
scheduling, you will have one interrupt every 23ms.


> 5) it seem bug in snd_pcm_sw_params_set_avail_min() since 4661 is larger
> than the buffer size 2048 since PA still think that 371ms is the maximum
> buffer size
>
>
> D: alsa-util.c:   buffer_size  : 2048
> D: alsa-util.c:   period_size  : 1024
> D: alsa-util.c:   period_time  : 23219
> D: alsa-util.c:   tstamp_mode  : NONE
> D: alsa-util.c:   period_step  : 1
> D: alsa-util.c:   avail_min    : 4661

This doesn't make sense. But avail_min isn't really used with the
timer-based scheduling

>
> For pulseaudio-0.9.14 on Fedora 10

Man, you are using an old version here, the alsa sink code was changed
several times already.