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ALSA: asihpi - Improve non-busmaster adapter operation 

Make playback silence callback a no-op, card automatically outputs
silence when written data runs out.
Increasing update interval and thus minimum period avoids xrun on startup
or because of timer jitter.

Signed-off-by: Eliot Blennerhassett <eblennerhassett@audioscience.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
hifive-unleashed-5.1
Eliot Blennerhassett 2011-03-25 15:25:47 +13:00 committed by Takashi Iwai
parent 7bf76c33e9
commit 26aebef420
1 changed files with 10 additions and 11 deletions
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21
sound/pci/asihpi/asihpi.c
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@ -1012,6 +1012,7 @@ static int snd_card_asihpi_playback_open(struct snd_pcm_substream *substream)
snd_pcm_hw_constraint_step(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
card->update_interval_frames);
snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
card->update_interval_frames * 2, UINT_MAX);
@ -1054,7 +1055,7 @@ static int snd_card_asihpi_playback_copy(struct snd_pcm_substream *substream,
hpi_handle_error(hpi_outstream_write_buf(dpcm->h_stream,
runtime->dma_area, len, &dpcm->format));
dpcm->pcm_buf_host_rw_ofs = dpcm->pcm_buf_host_rw_ofs + len;
dpcm->pcm_buf_host_rw_ofs += len;
return 0;
}
@ -1064,16 +1065,11 @@ static int snd_card_asihpi_playback_silence(struct snd_pcm_substream *
snd_pcm_uframes_t pos,
snd_pcm_uframes_t count)
{
unsigned int len;
struct snd_pcm_runtime *runtime = substream->runtime;
struct snd_card_asihpi_pcm *dpcm = runtime->private_data;
len = frames_to_bytes(runtime, count);
VPRINTK1(KERN_INFO "playback silence %u bytes\n", len);
memset(runtime->dma_area, 0, len);
hpi_handle_error(hpi_outstream_write_buf(dpcm->h_stream,
runtime->dma_area, len, &dpcm->format));
/* Usually writes silence to DMA buffer, which should be overwritten
by real audio later. Our fifos cannot be overwritten, and are not
free-running DMAs. Silence is output on fifo underflow.
This callback is still required to allow the copy callback to be used.
*/
return 0;
}
@ -2885,6 +2881,9 @@ static int __devinit snd_asihpi_probe(struct pci_dev *pci_dev,
if (err)
asihpi->update_interval_frames = 512;
if (!asihpi->support_mmap)
asihpi->update_interval_frames *= 2;
hpi_handle_error(hpi_instream_open(asihpi->adapter_index,
0, &h_stream));