lkml.org 
[lkml]   [2021]   [Aug]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v10 18/21] uvcvideo: improve error handling in uvc_query_ctrl()
Hi Ricardo and Hans,

Thank you for the patch.

Please add a "media: " prefix to the subject line. Same for the other
patches in the series that are missing this.

On Fri, Jun 18, 2021 at 02:29:20PM +0200, Ricardo Ribalda wrote:
> From: Hans Verkuil <hverkuil-cisco@xs4all.nl>
>
> - 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.
>
> - For error 2 (Wrong state) return -EACCES instead of -EILSEQ.
> EACCES is a much more appropriate error code. EILSEQ will return
> "Invalid or incomplete multibyte or wide character." in strerror(),
> which is a *very* confusing message.

I would still have split the patch in two :-)

> Reviewed-by: Ricardo Ribalda <ribalda@chromium.org>
> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> ---
> drivers/media/usb/uvc/uvc_video.c | 38 ++++++++++++++++++-------------
> 1 file changed, 22 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> index daba5fe352ea..00488f15cdbf 100644
> --- a/drivers/media/usb/uvc/uvc_video.c
> +++ b/drivers/media/usb/uvc/uvc_video.c
> @@ -79,15 +79,11 @@ 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)
> - return ret;
> + if (ret < 0 && ret != -EPIPE)

What if ret >= 0 ? There's a change of behaviour here that isn't
documented in the commit message. It shouldn't happen, but it would be
nice to handle it correctly.

> + goto err;
>
> + /* reuse data[0] to request the error code. */
> tmp = *(u8 *)data;
> -
> ret = __uvc_query_ctrl(dev, UVC_GET_CUR, 0, intfnum,
> UVC_VC_REQUEST_ERROR_CODE_CONTROL, data, 1,
> UVC_CTRL_CONTROL_TIMEOUT);
> @@ -95,19 +91,21 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit,
> error = *(u8 *)data;
> *(u8 *)data = tmp;
>
> - if (ret != 1)
> - return ret < 0 ? ret : -EPIPE;
> + if (ret != 1) {
> + ret = ret < 0 ? ret : -EPIPE;
> + goto err;

This will print an error message that doesn't match the error.

> + }
>
> - uvc_dbg(dev, CONTROL, "Control error %u\n", error);
> + if (error >=1 && error <=8)

Missing space before 1 and 8.

> + uvc_dbg(dev, CONTROL,
> + "Failed to query (%s) UVC control %u on unit %u: got error %u.\n",
> + uvc_query_name(query), cs, unit, error);
>
> switch (error) {
> - case 0:
> - /* Cannot happen - we received a STALL */
> - return -EPIPE;
> case 1: /* Not ready */
> return -EBUSY;
> case 2: /* Wrong state */
> - return -EILSEQ;
> + return -EACCES;
> case 3: /* Power */
> return -EREMOTE;
> case 4: /* Out of range */
> @@ -123,10 +121,18 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit,
> case 8: /* Invalid value within range */
> return -EINVAL;
> default: /* reserved or unknown */
> - break;
> + dev_err(&dev->udev->dev,
> + "Failed to query (%s) UVC control %u on unit %u: got error %u.\n",
> + uvc_query_name(query), cs, unit, error);
> + return -EPIPE;
> }
>
> - return -EPIPE;
> +err:
> + 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;
> }
>
> static void uvc_fixup_video_ctrl(struct uvc_streaming *stream,

--
Regards,

Laurent Pinchart

\
 
 \ /
  Last update: 2021-08-23 01:53    [W:0.153 / U:0.164 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site