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dmaengine: zx: fix residue calculation

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The dma residue is defined as the free space to end of transfer buffer,
which could be multiple segments chained together.  So the residue
calculation in zx_dma_tx_status() works for both slave_sg and cyclic
case.  But unfortunately, the 'index' is wrong.  It should plus one,
because the current segment is already occupied and shouldn't be counted
into free space.

This fixes the HDMI audio noise issue we see on ZX296718 with SPDIF
interface.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Jun Nie <jun.nie@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Shawn Guo 2016-12-15 22:03:37 +08:00 committed by Vinod Koul
parent fc318d64f3
commit 156ae09245
1 changed files with 2 additions and 1 deletions
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3
drivers/dma/zx_dma.c
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@ -365,7 +365,8 @@ static enum dma_status zx_dma_tx_status(struct dma_chan *chan,
bytes = 0;
clli = zx_dma_get_curr_lli(p);
index = (clli - ds->desc_hw_lli) / sizeof(struct zx_desc_hw);
index = (clli - ds->desc_hw_lli) /
sizeof(struct zx_desc_hw) + 1;
for (; index < ds->desc_num; index++) {
bytes += ds->desc_hw[index].src_x;
/* end of lli */