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[RFC] dai: dma_buffer: fix pop noise issue when start playback #2573

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Merged
lgirdwood merged 1 commit into from
Mar 20, 2020
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[RFC] dai: dma_buffer: fix pop noise issue when start playback #2573

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6 changes: 2 additions & 4 deletions src/audio/dai.c
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Original file line number Diff line number Diff line change
Expand Up @@ -503,10 +503,8 @@ static int dai_prepare(struct comp_dev *dev)
return -EINVAL;
}

/* TODO: not sure what this wb is for? */
/* write back buffer contents from cache */
dcache_writeback_region(dd->dma_buffer->stream.addr,
dd->dma_buffer->stream.size);
/* clear dma buffer to avoid pop noise */
buffer_zero(dd->dma_buffer);
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@plbossart plbossart Mar 18, 2020

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does this also force the zeroed data to be written back?

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@RanderWang RanderWang Mar 19, 2020

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good question. This function does it.

static inline void buffer_zero(struct comp_buffer *buffer)
{
	tracev_buffer_with_ids(buffer, "stream_zero()");

	bzero(buffer->stream.addr, buffer->stream.size);
	if (buffer->caps & SOF_MEM_CAPS_DMA)
		dcache_writeback_region(buffer->stream.addr,
					buffer->stream.size);
}


/* dma reconfig not required if XRUN handling */
if (dd->xrun) {
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