From: Eliot Blennerhassett eblennerhassett@audioscience.com
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 --- pci/asihpi/asihpi.c | 21 ++++++++++----------- 1 files changed, 10 insertions(+), 11 deletions(-)
diff --git a/pci/asihpi/asihpi.c b/pci/asihpi/asihpi.c index 22606e3..c90d77a 100644 --- a/pci/asihpi/asihpi.c +++ b/pci/asihpi/asihpi.c @@ -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));