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ALSA: dmaengine_pcm: Consider DMA cache caused delay in pointer callback

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Some DMA engines can have big FIFOs which adds to the latency.
The DMAengine framework can report the FIFO utilization in bytes. Use this
information for the delay reporting.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20200210153336.10218-1-peter.ujfalusi@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Peter Ujfalusi 2020-02-10 17:33:36 +02:00 committed by Mark Brown
parent b56be800f1
commit 9d789dc047
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GPG Key ID: 24D68B725D5487D0
1 changed files with 2 additions and 1 deletions
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sound/core/pcm_dmaengine.c
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@ -240,6 +240,7 @@ EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer_no_residue);
snd_pcm_uframes_t snd_dmaengine_pcm_pointer(struct snd_pcm_substream *substream) snd_pcm_uframes_t snd_dmaengine_pcm_pointer(struct snd_pcm_substream *substream)
{ {
struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream); struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
struct snd_pcm_runtime *runtime = substream->runtime;
struct dma_tx_state state; struct dma_tx_state state;
enum dma_status status; enum dma_status status;
unsigned int buf_size; unsigned int buf_size;
@ -257,7 +258,7 @@ snd_pcm_uframes_t snd_dmaengine_pcm_pointer(struct snd_pcm_substream *substream)
state.in_flight_bytes); state.in_flight_bytes);
} }
return bytes_to_frames(substream->runtime, pos); return bytes_to_frames(runtime, pos);
} }
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer); EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer);