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authorMark Brown <broonie@opensource.wolfsonmicro.com>2011-06-13 12:14:07 +0100
committerGreg Kroah-Hartman <gregkh@suse.de>2011-08-08 10:23:06 -0700
commit32910025980f24cab5061901d9b1249c2b2574b2 (patch)
treed5df46b45e4f82d8489afe8554d8c25a164ba518 /sound
parentd0a11cb1254411fd1d60084cd8498e8512cd6075 (diff)
ASoC: Fix Blackfin I2S _pointer() implementation return in bounds values
commit e999dc50404d401150a5429b6459473a691fd1a0 upstream. The Blackfin DMA controller can report one frame beyond the end of the buffer in the wraparound case but ALSA requires that the pointer always be in the buffer. Do the wraparound to handle this. A similar bug is likely to apply to the other Blackfin PCM drivers but the code is less obvious to inspection and I don't have a user to test. Reported-by: Kieran O'Leary <Kieran.O'Leary@wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@ti.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'sound')
-rw-r--r--sound/soc/blackfin/bf5xx-i2s-pcm.c13
1 files changed, 11 insertions, 2 deletions
diff --git a/sound/soc/blackfin/bf5xx-i2s-pcm.c b/sound/soc/blackfin/bf5xx-i2s-pcm.c
index 62fbb8459569..77dae1643997 100644
--- a/sound/soc/blackfin/bf5xx-i2s-pcm.c
+++ b/sound/soc/blackfin/bf5xx-i2s-pcm.c
@@ -139,11 +139,20 @@ static snd_pcm_uframes_t bf5xx_pcm_pointer(struct snd_pcm_substream *substream)
pr_debug("%s enter\n", __func__);
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
diff = sport_curr_offset_tx(sport);
- frames = bytes_to_frames(substream->runtime, diff);
} else {
diff = sport_curr_offset_rx(sport);
- frames = bytes_to_frames(substream->runtime, diff);
}
+
+ /*
+ * TX at least can report one frame beyond the end of the
+ * buffer if we hit the wraparound case - clamp to within the
+ * buffer as the ALSA APIs require.
+ */
+ if (diff == snd_pcm_lib_buffer_bytes(substream))
+ diff = 0;
+
+ frames = bytes_to_frames(substream->runtime, diff);
+
return frames;
}