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Subject[PATCH] dmaengine/dw_dmac fix: dwc_scan_descriptors must compare first desc address also with llp
dwc_scan_descriptors scans all descriptors from active_list in case transfer is
not completed. It compares first_desc->, and then all childrens of its
tx_list. But it doesn't compare its own address, i.e. first_desc->txd.phys, as
this is what we have initially programmed into the controller register. So this
causes dma to stop and finish a transfer, which was never started. And thus

Signed-off-by: Viresh Kumar <>
drivers/dma/dw_dmac.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index b95e6d3..1bd4803 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -304,6 +304,11 @@ static void dwc_scan_descriptors(struct dw_dma *dw, struct dw_dma_chan *dwc)
dev_vdbg(chan2dev(&dwc->chan), "scan_descriptors: llp=0x%x\n", llp);

list_for_each_entry_safe(desc, _desc, &dwc->active_list, desc_node) {
+ /* check first descriptors addr */
+ if (desc->txd.phys == llp)
+ return;
+ /* check first descriptors llp */
if (desc-> == llp)
/* This one is currently in progress */

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