Re: [PATCH v3 2/8] media: uvcvideo: improve error logging in uvc_query_ctrl()

From: Laurent Pinchart
Date: Tue Jan 03 2023 - 15:13:49 EST


Hi Ricardo,

Thank you for the patch.

On Tue, Jan 03, 2023 at 03:36:20PM +0100, Ricardo Ribalda wrote:
> From: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
>
> Standard use of the driver may result in error messages on the kernel
> ring buffer. This can hide other more important messages, and alert

I assume you meant log (or log buffer), not ring buffer. I'll fix that
when applying.

Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>

> unnecessarily the user. Let's keep dev_err() for the important
> occasions.
>
> If __uvc_query_ctrl() failed with a non -EPIPE error, then report that
> with dev_err. If an error code is obtained, then report that with
> dev_dbg.
>
> Reviewed-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> ---
> drivers/media/usb/uvc/uvc_video.c | 11 ++++++-----
> 1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> index d2eb9066e4dc..6b20a23bc3cf 100644
> --- a/drivers/media/usb/uvc/uvc_video.c
> +++ b/drivers/media/usb/uvc/uvc_video.c
> @@ -79,13 +79,14 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit,
> if (likely(ret == size))
> return 0;
>
> - dev_err(&dev->udev->dev,
> - "Failed to query (%s) UVC control %u on unit %u: %d (exp. %u).\n",
> - uvc_query_name(query), cs, unit, ret, size);
> -
> - if (ret != -EPIPE)
> + if (ret != -EPIPE) {
> + dev_err(&dev->udev->dev,
> + "Failed to query (%s) UVC control %u on unit %u: %d (exp. %u).\n",
> + uvc_query_name(query), cs, unit, ret, size);
> return ret;
> + }
>
> + /* Reuse data[0] to request the error code. */
> tmp = *(u8 *)data;
>
> ret = __uvc_query_ctrl(dev, UVC_GET_CUR, 0, intfnum,

--
Regards,

Laurent Pinchart