Re: [PATCH v5 2/2] media: uvcvideo: Add more logging to uvc_query_ctrl()

[Laurent Pinchart]

On Thu, Nov 28, 2024 at 08:53:42PM +0000, Ricardo Ribalda wrote:
> If we fail to query the ctrl error code there is no information on dmesg

s/ctrl/control/

> or in uvc_dbg. This makes difficult to debug the issue.
> 
> Print a proper error message when we cannot retrieve the error code from
> the device.
> 
> Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>

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

I'll update the commit message, no need to resend.

> ---
>  drivers/media/usb/uvc/uvc_video.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> index 67f714bca417..a650d886e922 100644
> --- a/drivers/media/usb/uvc/uvc_video.c
> +++ b/drivers/media/usb/uvc/uvc_video.c
> @@ -117,8 +117,12 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit,
>  	error = *(u8 *)data;
>  	*(u8 *)data = tmp;
>  
> -	if (ret != 1)
> +	if (ret != 1) {
> +		dev_err_ratelimited(&dev->udev->dev,
> +				    "Failed to query (%s) UVC error code control %u on unit %u: %d (exp. 1).\n",
> +				    uvc_query_name(query), cs, unit, ret);
>  		return ret < 0 ? ret : -EPIPE;
> +	}
>  
>  	uvc_dbg(dev, CONTROL, "Control error %u\n", error);
>  

-- 
Regards,

Laurent Pinchart