On Mon, Mar 19, 2007 at 03:30:33PM -0400, Rich Rattanni wrote:
> On 3/19/07, Takashi Iwai <tiwai@xxxxxxx> wrote:
> > At Mon, 19 Mar 2007 12:31:16 -0400,
> > Rich Rattanni wrote:
> > >
> > > All:
> > >
> > > I have noticed a strange behaviour in the ALSA driver that seems to be
> > > occur after initiating a power standby and resume. I am working on an
> > > application that uses FusionSound to playback OGG audio files. When
> > > the application recognizes it is idle, it tells the OS to enter
> > > standby mode. Upon resuming from standby, the ALSA API call made by
> > > fusionsound no longer acts as a blocking read, instead it returns
> > > immediately. I have confirmed this with Denis Oliver Kropp of the
> > > DirectFB / FusionSound project. He suggested that the ALSA driver
> > > should be repaired to prevent this problem from occuring.
> >
> > It's not clear what is happening there.
> > Do you have a small testcase?
> >
> > When the suspend/resume happens, the apps is usually requested to call
> > snd_pcm_resume() and/or snd_pcm_prepare() appropriately to reset the
> > stream. Otherwise the PCM status is kept as SUSPENDED.
<snip>
>
> static void
> device_write( void *device_data, void *samples, unsigned int size )
> {
> AlsaDeviceData *data = device_data;
> snd_pcm_uframes_t frames = size;
> snd_pcm_sframes_t r;
> u8 *src;
>
> src = samples;
> while (frames) {
> r = snd_pcm_writei( data->handle, src, frames );
Maybe we just need to add something like this here?
+ if (r == -ESTRPIPE) {
+ while ((r = snd_pcm_resume( data->handle )) == -EAGAIN)
+ sleep( 1 );
+ }
> if (r < 0) {
> r = snd_pcm_prepare( data->handle );
> if (r < 0) {
> D_WARN( "FusionSound/Device/ALSA: snd_pcm_writei()
> failed: %s\n",
> snd_strerror( r ) );
> break;
> }
> continue;
> }
> frames -= r;
> src += snd_pcm_frames_to_bytes( data->handle, r );
> }
> }
--
Ville Syrjälä
syrjala@xxxxxx
http://www.sci.fi/~syrjala/
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