[PATCH 6/6] ASoC/mpc5200: Add fudge factor to value reported by .pointer()

Grant Likely grant.likely at secretlab.ca
Sat Nov 7 19:34:55 EST 2009


ALSA playback seems to be more reliable if the .pointer() hook reports
a value slightly into the period, rather than right on the period
boundary.  This patch adds a fudge factor of 1/4 the period size
to better estimate the actual position of the DMA engine in the
audio buffer.

Signed-off-by: Grant Likely <grant.likely at secretlab.ca>
---

 sound/soc/fsl/mpc5200_dma.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/sound/soc/fsl/mpc5200_dma.c b/sound/soc/fsl/mpc5200_dma.c
index 9c88e15..ee5a606 100644
--- a/sound/soc/fsl/mpc5200_dma.c
+++ b/sound/soc/fsl/mpc5200_dma.c
@@ -297,7 +297,7 @@ psc_dma_pointer(struct snd_pcm_substream *substream)
 	else
 		s = &psc_dma->playback;
 
-	count = s->period_current * s->period_bytes;
+	count = (s->period_current * s->period_bytes) + (s->period_bytes >> 2);
 
 	return bytes_to_frames(substream->runtime, count);
 }



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