diff mbox series

[3/4] dmaengine: xilinx: dpdma: Print debug message when losing vsync race

Message ID 20210520152420.23986-4-laurent.pinchart@ideasonboard.com (mailing list archive)
State New, archived
Headers show
Series dmaengine: xilinx: dpdma: Fix freeze after 64k frames | expand

Commit Message

Laurent Pinchart May 20, 2021, 3:24 p.m. UTC 
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>
---
 drivers/dma/xilinx/xilinx_dpdma.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
diff mbox series

Patch

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