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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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      Last update: 2011-03-24 07:05    [W:0.019 / U:24.032 seconds]
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