Re: [PATCH v3 2/5] media: uvcvideo: Use uvc_warn_once when it make sense

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Fri, Sep 11, 2026 at 01:22:26PM +0000, Ricardo Ribalda wrote:
> If there are multiple cameras in the system affected by a compliance
> error now we only show an error message for one of them.
> 
> Use uvc_warn_once() to print an error message per device.
> 
> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> ---
>  drivers/media/usb/uvc/uvc_video.c | 2 +-
>  drivers/media/usb/uvc/uvcvideo.h  | 1 +
>  2 files changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> index fc3536a4399f..2a3b7431cc68 100644
> --- a/drivers/media/usb/uvc/uvc_video.c
> +++ b/drivers/media/usb/uvc/uvc_video.c
> @@ -95,7 +95,7 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit,
>  	 */
>  	if (ret > 0 && query != UVC_GET_INFO) {
>  		memset(data + ret, 0, size - ret);
> -		dev_warn_once(&dev->intf->dev,
> +		uvc_warn_once(dev, UVC_WARN_QUERY_CTRL,

I thought about submitting a patch for this when I read 1/5 :-)

The only other usage of dev_warn_once() in the driver logs bad access to
the privacy control from userspace, which doesn't need to be logged per
device.

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

>  			      "UVC non compliance: %s control %u on unit %u returned %d bytes when we expected %u.\n",
>  			      uvc_query_name(query), cs, unit, ret, size);
>  		return 0;
> diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> index a80406f20beb..abcafd929c9e 100644
> --- a/drivers/media/usb/uvc/uvcvideo.h
> +++ b/drivers/media/usb/uvc/uvcvideo.h
> @@ -661,6 +661,7 @@ static inline struct uvc_fh *to_uvc_fh(struct file *filp)
>  #define UVC_WARN_MINMAX		0
>  #define UVC_WARN_PROBE_DEF	1
>  #define UVC_WARN_XU_GET_RES	2
> +#define UVC_WARN_QUERY_CTRL	3
>  
>  extern unsigned int uvc_clock_param;
>  extern unsigned int uvc_no_drop_param;

-- 
Regards,

Laurent Pinchart