From 4fbf41ce573556a6dc4e684f0d92700cdc883ad3 Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Thu, 20 May 2021 18:24:19 +0300 Subject: [PATCH] dmaengine: xilinx: dpdma: Print debug message when losing vsync race 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 Tested-by: Jianqiang Chen Reviewed-by: Jianqiang Chen Link: https://lore.kernel.org/r/20210520152420.23986-4-laurent.pinchart@ideasonboard.com Signed-off-by: Vinod Koul --- 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 ea56c3b..5834f86 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 -- 2.7.4