[alsa-devel] ALC892 optical SPDIF not working

[Takashi Iwai]

At Thu, 5 Aug 2010 20:52:28 +0200,
Manuel Lauss wrote:
> 
> On Mon, Aug 02, 2010 at 06:03:32PM +0200, Takashi Iwai wrote:
> > At Mon, 02 Aug 2010 10:02:48 +0200,
> > I wrote:
> > > 
> > > At Sun, 1 Aug 2010 01:32:23 +0200,
> > > Manuel Lauss wrote:
> > > > 
> > > > > > >> Is there a way to insert an initial playback delay?  Under linux, the
> > > > > > >> first 2-2.5 seconds
> > > > > > >> of anything played are just silence; on windows audible playback
> > > > > > >> starts immediately.
> > > > > > >
> > > > > > > It's the time for synchronization your digital receiver takes, I guess.
> > > > > > > Maybe changing SPDIF status makes it resync, which happens at each
> > > > > > > opening / closing the stream.
> > > > > > 
> > > > > > Yes, seems so. I've found a workaround in meantime.
> > > > > 
> > > > > Could you elaborate on the workaround please, so others having this
> > > > > issue know it.
> > > > 
> > > > My receiver allows to mix analog and digital inputs; with analog mix
> > > > enabled it syncs immediately.
> > > 
> > > Just wondering whether the patch below helps?
> > > 
> > > It's just a proof-of-concept, and it's not safe for multiple streams.
> > > If this works, we can move on the improvement of the stream assignment.
> > 
> > ... and the below is the patch.  If the previous patch worked, try
> > this instead of the previous one.
> 
> 
> Tested with mplayer.  The initial 2-2.5sec silence is still there (on every
> invocation of mplayer), but seeking now works as it should (previously
> there was 2 sec silence too).  Disabling codec pm doesn't help.

OK, it's a slight improvement.  Now the question is why it still happens
at each invocation of mplayer.  Assuming that it's no power-save, one
possible explanation is the call of azx_stream_reset() in prepare.
But, then this should happen at each seek, too.

Could you put some printk's and check whether AC_VERB_SET_CHANNEL_STREAMID
and/or AC_VERB_GET_STREAM_FORMAT verbs are executed at each time or
properly cached?


thanks,

Takashi