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ASoC/mpc5200: get rid of the appl_ptr tracking nonsense

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Sound drivers PCM DMA is supposed to free-run until told to stop
by the trigger callback.  The current code tries to track appl_ptr,
to avoid stale buffer data getting played out at the end of the
data stream.  Unfortunately it also results in race conditions
which can cause the audio to stall.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This commit is contained in:
Grant Likely 2009-11-07 01:34:05 -07:00 committed by Mark Brown
parent 8f159d720b
commit d56b6eb6df
2 changed files with 8 additions and 46 deletions
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52
sound/soc/fsl/mpc5200_dma.c
View file

@ -65,36 +65,6 @@ static void psc_dma_bcom_enqueue_next_buffer(struct psc_dma_stream *s)
s->period_next = (s->period_next + 1) % s->runtime->periods;
}
static void psc_dma_bcom_enqueue_tx(struct psc_dma_stream *s)
{
if (s->appl_ptr > s->runtime->control->appl_ptr) {
/*
* In this case s->runtime->control->appl_ptr has wrapped around.
* Play the data to the end of the boundary, then wrap our own
* appl_ptr back around.
*/
while (s->appl_ptr < s->runtime->boundary) {
if (bcom_queue_full(s->bcom_task))
return;
s->appl_ptr += s->runtime->period_size;
psc_dma_bcom_enqueue_next_buffer(s);
}
s->appl_ptr -= s->runtime->boundary;
}
while (s->appl_ptr < s->runtime->control->appl_ptr) {
if (bcom_queue_full(s->bcom_task))
return;
s->appl_ptr += s->runtime->period_size;
psc_dma_bcom_enqueue_next_buffer(s);
}
}
/* Bestcomm DMA irq handler */
static irqreturn_t psc_dma_bcom_irq_tx(int irq, void *_psc_dma_stream)
{
@ -107,8 +77,9 @@ static irqreturn_t psc_dma_bcom_irq_tx(int irq, void *_psc_dma_stream)
bcom_retrieve_buffer(s->bcom_task, NULL, NULL);
s->period_current = (s->period_current+1) % s->runtime->periods;
psc_dma_bcom_enqueue_next_buffer(s);
}
psc_dma_bcom_enqueue_tx(s);
spin_unlock(&s->psc_dma->lock);
/* If the stream is active, then also inform the PCM middle layer
@ -182,28 +153,21 @@ static int psc_dma_trigger(struct snd_pcm_substream *substream, int cmd)
s->period_next = 0;
s->period_current = 0;
s->active = 1;
/* track appl_ptr so that we have a better chance of detecting
* end of stream and not over running it.
*/
s->runtime = runtime;
s->appl_ptr = s->runtime->control->appl_ptr -
(runtime->period_size * runtime->periods);
/* Fill up the bestcomm bd queue and enable DMA.
* This will begin filling the PSC's fifo.
*/
spin_lock_irqsave(&psc_dma->lock, flags);
if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE) {
if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE)
bcom_gen_bd_rx_reset(s->bcom_task);
for (i = 0; i < runtime->periods; i++)
if (!bcom_queue_full(s->bcom_task))
psc_dma_bcom_enqueue_next_buffer(s);
} else {
else
bcom_gen_bd_tx_reset(s->bcom_task);
psc_dma_bcom_enqueue_tx(s);
}
for (i = 0; i < runtime->periods; i++)
if (!bcom_queue_full(s->bcom_task))
psc_dma_bcom_enqueue_next_buffer(s);
bcom_enable(s->bcom_task);
spin_unlock_irqrestore(&psc_dma->lock, flags);

2
sound/soc/fsl/mpc5200_dma.h
View file

@ -19,8 +19,6 @@
*/
struct psc_dma_stream {
struct snd_pcm_runtime *runtime;
snd_pcm_uframes_t appl_ptr;
int active;
struct psc_dma *psc_dma;
struct bcom_task *bcom_task;