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From: Grant Likely <grant.likely@secretlab.ca>
To: linuxppc-dev@lists.ozlabs.org, alsa-devel@alsa-project.org,
	broonie@opensource.wolfsonmicro.com
Cc: lrg@slimlogic.co.uk
Subject: [PATCH 6/6] ASoC/mpc5200: Add fudge factor to value reported by .pointer()
Date: Sat, 07 Nov 2009 01:34:55 -0700	[thread overview]
Message-ID: <20091107083448.18908.80366.stgit@angua> (raw)
In-Reply-To: <20091107081631.18908.82921.stgit@angua>

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@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);
 }

  parent reply	other threads:[~2009-11-07  8:34 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-11-07  8:33 [PATCH 0/6] Fixups to MPC5200 ASoC drivers Grant Likely
2009-11-07  8:33 ` [PATCH 1/6] ASoC/mpc5200: Track DMA position by period number instead of bytes Grant Likely
2009-11-07 10:35   ` [alsa-devel] " Liam Girdwood
2009-11-07 16:50     ` Grant Likely
2009-11-07  8:34 ` [PATCH 2/6] ASoC/mpc5200: get rid of the appl_ptr tracking nonsense Grant Likely
2009-11-07 12:51   ` Jon Smirl
2009-11-07 13:04     ` Jon Smirl
2009-11-07 18:53       ` Grant Likely
2009-11-07 18:51     ` Grant Likely
2009-11-07 20:12       ` [alsa-devel] " Mark Brown
2009-11-11 16:38         ` Jon Smirl
2009-11-11 18:37           ` Mark Brown
2009-11-11 19:24             ` Grant Likely
2009-11-11 20:03               ` Mark Brown
2009-11-11 21:34               ` Jon Smirl
2009-11-11 21:57                 ` Grant Likely
2009-11-11 23:13                   ` Jon Smirl
2009-11-12 12:10                     ` Mark Brown
2009-11-11 21:26             ` Jon Smirl
2009-11-07  8:34 ` [PATCH 3/6] ASoC/mpc5200: Improve printk debug output for trigger Grant Likely
2009-11-07  8:34 ` [PATCH 4/6] ASoC/mpc5200: add to_psc_dma_stream() helper Grant Likely
2009-11-07 12:33   ` [alsa-devel] " Mark Brown
2009-11-07  8:34 ` [PATCH 5/6] ASoC/mpc5200: fix enable/disable of AC97 slots Grant Likely
2009-11-07  8:34 ` Grant Likely [this message]
2009-11-07 18:11   ` [alsa-devel] [PATCH 6/6] ASoC/mpc5200: Add fudge factor to value reported by .pointer() Mark Brown
2009-11-07 18:19     ` Grant Likely
2009-11-07 19:33       ` Mark Brown
2009-11-07 19:46         ` Grant Likely
2009-11-07 12:57 ` [alsa-devel] [PATCH 0/6] Fixups to MPC5200 ASoC drivers Mark Brown
2009-11-07 16:52   ` Grant Likely

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