[alsa-devel] snd-es1968 capture broken

[Takashi Iwai]

At Wed, 28 Mar 2007 15:15:28 +0200,
Rene Herman wrote:
> 
> On 03/28/2007 01:40 PM, Takashi Iwai wrote:
> 
> > At Wed, 28 Mar 2007 13:03:51 +0200,
> > Rene Herman wrote:
> 
> >>> Bingo, that's it. "arecord --period-size=4096 --buffer-size=16384 -f cd" 
> >>> works fine. I guess it should be forcing power of 2 then?
> >> Only --period-size=4096 is not enough. It then has a buffer-size of
> >> 22016 and the stutter is there.
> >>
> >> --buffer-size=8192 --period-size=4000 is fine though. So, buffer-size...
> > 
> > You can try snd_pcm_hw_constraint_pow2() there.
> 
> Seems to work nicely! With the attached, a simple "arecord -f cd" works 
> without problem (it then sets buffer_size 16384, period_size 4096) and 
> seems to be settling on the nearest power of two if I pass something in 
> for buffer_size manually.
> 
> > But, IIRC, power-of-two constraint causes problems when you use
> > buffer_time instead of buffer_size. Anyway, worth try once.
> 
> I don't seem to be experiencing problems there either;
> 
>    command                            | buffer_size/period_size
>    ------------------------------------------------------------
>    arecord -f cd --buffer-time 100000 |  4096/1103
>    arecord -f cd --buffer-time 150000 |  8192/1654
>    arecord -f cd --buffer-time 200000 | 16384/2205
> 
> These all work fine. With --period-time:
> 
>    command                           | buffer_size/period_size
>    -----------------------------------------------------------
>    arecord -f cd --period-time 20000 | 16384/882
>    arecord -f cd --period-time 35000 | 16384/1544
>    arecord -f cd --period-time 50000 | 16384/2205
> 
> All fine again. If I try upsetting the thing on purpose with large 
> values, I get errors (from arecord, not in the sound).
> 
> As far as I'm concerned this seems good to go. Signed-off-by/Tested-by 
> and all that.

OK, then it's good.  I applied the fix together with cleanup of
superfluous '#if 0's.


thanks,

Takashi

> 
> Rene.
> 
> [2 es1968_buffer_pow2.diff <text/plain (7bit)>]
> diff --git a/sound/pci/es1968.c b/sound/pci/es1968.c
> index dc84c18..8130a87 100644
> --- a/sound/pci/es1968.c
> +++ b/sound/pci/es1968.c
> @@ -1617,6 +1617,8 @@ #if 0
>  	snd_pcm_hw_constraint_step(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_BYTES,
>  				   1024);
>  #endif
> +	snd_pcm_hw_constraint_pow2(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_BYTES);
> +
>  	spin_lock_irq(&chip->substream_lock);
>  	list_add(&es->list, &chip->substream_list);
>  	spin_unlock_irq(&chip->substream_lock);