[alsa-devel] *SPAM* Re: Please help in adding ams-delta support to ASoC

[Janusz Krzysztofik]

Wednesday 03 June 2009 07:28:06 Peter Ujfalusi napisał(a):
> Looking at the code at commit: d8376cc482b241701f7606c81ad578b90853e175 on
> l-o the comment about the need for the call the omap_stop_dma puzzled me.

Peter,

It was omap_stop_alsa_sound_dma(), not just omap_stop_dma(), the was needed.
In my opinion, the reason for that was not because it was calling 
omap_stop_dma(), but because it was clearing the audio_stream.started flag. 
That way, subsequent audio_start_dma_chain() would not jump over 
omap_start_dma(). From my experience with the original driver, it worked much 
better when calling omap_start_dma() unconditionally from 
audio_start_dma_chain() instead of doing this with that 
omap_stop_alsa_sound_dma() trick.

> Can you try something like this:
>
> diff --git a/sound/soc/omap/omap-pcm.c b/sound/soc/omap/omap-pcm.c
> index 6454e15..2df1792 100644
> --- a/sound/soc/omap/omap-pcm.c
> +++ b/sound/soc/omap/omap-pcm.c
> @@ -67,6 +67,7 @@ static void omap_pcm_dma_irq(int ch, u16 stat, void
> *data) spin_lock_irqsave(&prtd->lock, flags);
>                 if (prtd->period_index >= 0) {
>                         if (++prtd->period_index == runtime->periods) {
> +                               omap_stop_dma(prtd->dma_ch);
>                                 prtd->period_index = 0;
>                                 omap_start_dma(prtd->dma_ch);
>                         }
> @@ -191,6 +192,7 @@ static int omap_pcm_trigger(struct snd_pcm_substream
> *substream, int cmd)
>         case SNDRV_PCM_TRIGGER_START:
>         case SNDRV_PCM_TRIGGER_RESUME:
>         case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
> +               omap_stop_dma(prtd->dma_ch);
>                 prtd->period_index = 0;
>                 omap_start_dma(prtd->dma_ch);
>                 break;

Never hurts. Unfortunatelly, it did not help, no single DMA interrupt again.

Thanks,
Janusz
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