[alsa-devel] Getting XRUN after writei in RUNNING state?

[Piers O'Hanlon]

Hi Jaroslav,

Just to let you know I'm running this on Ubuntu 7.10
(alsa-lib-1.0.14), though I've been seeing this underrun problem for a
while on a few systems (Ubuntu 7.04/6.10, and Gentoo 2006.1). It
hasn't been clear to me what the key parameters are that control
underrun behaviour. (It would be great if someone wrote a
comprehensive book/article on ALSA....)

BTW you mentioned doing the rate resampling in RAT - which it can do -
how does one discover if rate conversion is occurring in ALSA and
obtain that 'base' rate? (Though I has assumed that ALSA would do the
better job of rate resampling if it was necessary...).

Thanks,

Piers.

On 09/11/2007, Jaroslav Kysela <perex at perex.cz> wrote:
> On Fri, 9 Nov 2007, Piers O'Hanlon wrote:
>
> > ===snd_pcm_dump_setup:===============
> >   stream       : PLAYBACK
> >   access       : RW_INTERLEAVED
> >   format       : S16_LE
> >   subformat    : STD
> >   channels     : 1
> >   rate         : 16000
> >   exact rate   : 16000 (16000/1)
> >   msbits       : 16
> >   buffer_size  : 2048
> >   period_size  : 341
> >   period_time  : 21333
> >   tick_time    : 0
> >   tstamp_mode  : NONE
> >   period_step  : 1
> >   sleep_min    : 0
> >   avail_min    : 341
> >   xfer_align   : 1
> >   start_threshold  : 341
> >   stop_threshold   : 2048
> >   silence_threshold: 0
> >   silence_size : 0
> >   boundary     : 536870912
>
> Could you do whole dump (snd_pcm_dump()) to see all plugins in chain?
> I judge from period_size that we have another problem with rate plugin.
> It would be better to do rate resampling in RAT.
>
>                                                 Jaroslav
>
> -----
> Jaroslav Kysela <perex at perex.cz>
> Linux Kernel Sound Maintainer
> ALSA Project
>