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>
diff --git a/sound/pci/asihpi/asihpi.c b/sound/pci/asihpi/asihpi.c
index 22606e3..c90d77a 100644
--- a/sound/pci/asihpi/asihpi.c
+++ b/sound/pci/asihpi/asihpi.c
@@ -1012,6 +1012,7 @@
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 @@
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 @@
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 @@
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));