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authorDaniel Silsby <dansilsby@gmail.com>2018-08-29 23:32:56 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-11-25 15:53:51 +0100
commit8f0c1696ecd01ede1539c4e6a3f2a6850216b4e9 (patch)
tree550a6c1ea59a95c6c7b4e18d2421d92c332ed14e /drivers/dma
parentb8fac3d96f46cde91b64a1bead0a1cbfc40133be (diff)
dmaengine: dma-jz4780: Further residue status fix
[ Upstream commit 83ef4fb7556b6a673f755da670cbacab7e2c7f1b ] Func jz4780_dma_desc_residue() expects the index to the next hw descriptor as its last parameter. Caller func jz4780_dma_tx_status(), however, applied modulus before passing it. When the current hw descriptor was last in the list, the index passed became zero. The resulting excess of reported residue especially caused problems with cyclic DMA transfer clients, i.e. ALSA AIC audio output, which rely on this for determining current DMA location within buffer. Combined with the recent and related residue-reporting fixes, spurious ALSA audio underruns on jz4770 hardware are now fixed. Signed-off-by: Daniel Silsby <dansilsby@gmail.com> Signed-off-by: Paul Cercueil <paul@crapouillou.net> Tested-by: Mathieu Malaterre <malat@debian.org> Signed-off-by: Vinod Koul <vkoul@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/dma')
-rw-r--r--drivers/dma/dma-jz4780.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/dma/dma-jz4780.c b/drivers/dma/dma-jz4780.c
index 8344b7c91fe3..1d01e3805f9c 100644
--- a/drivers/dma/dma-jz4780.c
+++ b/drivers/dma/dma-jz4780.c
@@ -576,7 +576,7 @@ static enum dma_status jz4780_dma_tx_status(struct dma_chan *chan,
to_jz4780_dma_desc(vdesc), 0);
} else if (cookie == jzchan->desc->vdesc.tx.cookie) {
txstate->residue = jz4780_dma_desc_residue(jzchan, jzchan->desc,
- (jzchan->curr_hwdesc + 1) % jzchan->desc->count);
+ jzchan->curr_hwdesc + 1);
} else
txstate->residue = 0;