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dmaengine: xilinx: dpdma: Print debug message when losing vsync race

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The hardware retrigger is inherently racy with the vsync interrupt. This
isn't an issue as the hardware provides a way to detect a race loss and
handle it correctly. When debugging issues related to this, it's useful
to get a notification of the race loss. Add a debug message to do so.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Jianqiang Chen <jianqiang.chen@xilinx.com>
Reviewed-by: Jianqiang Chen <jianqiang.chen@xilinx.com>
Link: https://lore.kernel.org/r/20210520152420.23986-4-laurent.pinchart@ideasonboard.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Laurent Pinchart 2021-05-20 18:24:19 +03:00 committed by Vinod Koul
parent 3021190192
commit 4fbf41ce57
1 changed files with 5 additions and 1 deletions
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6
drivers/dma/xilinx/xilinx_dpdma.c
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@ -1095,8 +1095,12 @@ static void xilinx_dpdma_chan_vsync_irq(struct xilinx_dpdma_chan *chan)
/* If the retrigger raced with vsync, retry at the next frame. */
sw_desc = list_first_entry(&pending->descriptors,
struct xilinx_dpdma_sw_desc, node);
if (sw_desc->hw.desc_id != desc_id)
if (sw_desc->hw.desc_id != desc_id) {
dev_dbg(chan->xdev->dev,
"chan%u: vsync race lost (%u != %u), retrying\n",
chan->id, sw_desc->hw.desc_id, desc_id);
goto out;
}
/*
* Complete the active descriptor, if any, promote the pending