2023-01-03 14:42:23

by Ricardo Ribalda

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

From: Hans Verkuil <[email protected]>

Standard use of the driver may result in error messages on the kernel
ring buffer. This can hide other more important messages, and alert
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 <[email protected]>
Signed-off-by: Hans Verkuil <[email protected]>
---
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,

--
2.39.0.314.g84b9a713c41-goog-b4-0.11.0-dev-696ae

2023-01-03 20:22:20

by Ricardo Ribalda

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

Hi Laurent

On Tue, 3 Jan 2023 at 21:13, Laurent Pinchart
<[email protected]> wrote:
>
> Hi Ricardo,
>
> Thank you for the patch.
>
> On Tue, Jan 03, 2023 at 03:36:20PM +0100, Ricardo Ribalda wrote:
> > From: Hans Verkuil <[email protected]>
> >
> > 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.

I tried to use the best term. And I found this:
https://man7.org/linux/man-pages/man1/dmesg.1.html

seems that kernel ring buffer is the correct term (but I might confess
that I use dmesg or simply log)

In this case, anything works for me ;)

Thanks!

>
> Reviewed-by: Laurent Pinchart <[email protected]>
>
> > 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 <[email protected]>
> > Signed-off-by: Hans Verkuil <[email protected]>
> > ---
> > 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



--
Ricardo Ribalda

2023-01-03 20:26:04

by Laurent Pinchart

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

Hi Ricardo,

Thank you for the patch.

On Tue, Jan 03, 2023 at 03:36:20PM +0100, Ricardo Ribalda wrote:
> From: Hans Verkuil <[email protected]>
>
> 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 <[email protected]>

> 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 <[email protected]>
> Signed-off-by: Hans Verkuil <[email protected]>
> ---
> 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

2023-01-12 22:44:57

by Laurent Pinchart

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

Hi Hans,

On Tue, Jan 03, 2023 at 03:36:20PM +0100, Ricardo Ribalda wrote:
> From: Hans Verkuil <[email protected]>

There's also a mismatch here between From and Signed-off-by.

> Standard use of the driver may result in error messages on the kernel
> ring buffer. This can hide other more important messages, and alert
> 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 <[email protected]>
> Signed-off-by: Hans Verkuil <[email protected]>
> ---
> 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