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@xxxxxxxxxxxxxxxx>
---
drivers/dma/xilinx/xilinx_dpdma.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/dma/xilinx/xilinx_dpdma.c b/drivers/dma/xilinx/xilinx_dpdma.c
index ea56c3b35782..5834f8614a58 100644
--- a/drivers/dma/xilinx/xilinx_dpdma.c
+++ b/drivers/dma/xilinx/xilinx_dpdma.c
@@ -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
--
Regards,
Laurent Pinchart
