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

From: Ricardo Ribalda
Date: Tue Jan 03 2023 - 09:37:09 EST


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
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,

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