Hi Wang, Thank you for the patch. On Wed, Jul 26, 2023 at 07:51:58PM +0800, Wang Ming wrote: > It is possible that dma_request_chan will return EPROBE_DEFER, > which means that dma->xdev->dev is not ready yet. In this case, > dev_err(dma->xdev->dev), there will be no output. This patch > fixes the bug. It's not a bug. The existing code works as expected. dev_err_probe() is nicer though, as it records the reason for the probe deferral. Here's a proposal for a better commit message: It is possible that dma_request_chan() returns EPROBE_DEFER, in which case the driver defers probing without printing any message. Use dev_err_probe() to record the probe deferral cause and ease debugging. If you're fine with this, there's no need to resubmit, I'll update the commit message locally and merge the patch. Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > Signed-off-by: Wang Ming <machel@xxxxxxxx> > --- > drivers/media/platform/xilinx/xilinx-dma.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/drivers/media/platform/xilinx/xilinx-dma.c b/drivers/media/platform/xilinx/xilinx-dma.c > index 80d6f5b072ea..16ad39bef6c6 100644 > --- a/drivers/media/platform/xilinx/xilinx-dma.c > +++ b/drivers/media/platform/xilinx/xilinx-dma.c > @@ -708,9 +708,8 @@ int xvip_dma_init(struct xvip_composite_device *xdev, struct xvip_dma *dma, > snprintf(name, sizeof(name), "port%u", port); > dma->dma = dma_request_chan(dma->xdev->dev, name); > if (IS_ERR(dma->dma)) { > - ret = PTR_ERR(dma->dma); > - if (ret != -EPROBE_DEFER) > - dev_err(dma->xdev->dev, "no VDMA channel found\n"); > + ret = dev_err_probe(dma->xdev->dev, PTR_ERR(dma->dma), > + "no VDMA channel found\n"); > goto error; > } > -- Regards, Laurent Pinchart