Some cameras do not return all the bytes requested from a control if it can fit in less bytes. Eg: returning 0xab instead of 0x00ab. Support these devices.
Also, now that we are at it, improve uvc_query_ctrl() logging.
Signed-off-by: Ricardo Ribalda ribalda@chromium.org --- Changes in v5: - Improve comment. - Link to v4: https://lore.kernel.org/r/20241120-uvc-readless-v4-0-4672dbef3d46@chromium.o...
Changes in v4: - Improve comment. - Keep old likely(ret == size) - Link to v3: https://lore.kernel.org/r/20241118-uvc-readless-v3-0-d97c1a3084d0@chromium.o...
Changes in v3: - Improve documentation. - Do not change return sequence. - Use dev_ratelimit and dev_warn_once - Link to v2: https://lore.kernel.org/r/20241008-uvc-readless-v2-0-04d9d51aee56@chromium.o...
Changes in v2: - Rewrite error handling (Thanks Sakari) - Discard 2/3. It is not needed after rewriting the error handling. - Link to v1: https://lore.kernel.org/r/20241008-uvc-readless-v1-0-042ac4581f44@chromium.o...
--- Ricardo Ribalda (2): media: uvcvideo: Support partial control reads media: uvcvideo: Add more logging to uvc_query_ctrl()
drivers/media/usb/uvc/uvc_video.c | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-) --- base-commit: 9852d85ec9d492ebef56dc5f229416c925758edc change-id: 20241008-uvc-readless-23f9b8cad0b3
Best regards,
Some cameras, like the ELMO MX-P3, do not return all the bytes requested from a control if it can fit in less bytes. Eg: Returning 0xab instead of 0x00ab. usb 3-9: Failed to query (GET_DEF) UVC control 3 on unit 2: 1 (exp. 2).
Extend the returned value from the camera and return it.
Cc: stable@vger.kernel.org Fixes: a763b9fb58be ("media: uvcvideo: Do not return positive errors in uvc_query_ctrl()") Reviewed-by: Hans de Goede hdegoede@redhat.com Signed-off-by: Ricardo Ribalda ribalda@chromium.org --- drivers/media/usb/uvc/uvc_video.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)
diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c index cd9c29532fb0..67f714bca417 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -79,6 +79,27 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit, if (likely(ret == size)) return 0;
+ /* + * Some devices return shorter USB control packets than expected if the + * returned value can fit in less bytes. Zero all the bytes that the + * device has not written. + * + * This quirk is applied to all controls, regardless of their data type. + * Most controls are little-endian integers, in which case the missing + * bytes become 0 MSBs. For other data types, a different heuristic + * could be implemented if a device is found needing it. + * + * We exclude UVC_GET_INFO from the quirk. UVC_GET_LEN does not need + * to be excluded because its size is always 1. + */ + if (ret > 0 && query != UVC_GET_INFO) { + memset(data + ret, 0, size - ret); + dev_warn_once(&dev->udev->dev, + "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; + } + if (ret != -EPIPE) { dev_err(&dev->udev->dev, "Failed to query (%s) UVC control %u on unit %u: %d (exp. %u).\n",
On Thu, Nov 28, 2024 at 08:53:41PM +0000, Ricardo Ribalda wrote:
Some cameras, like the ELMO MX-P3, do not return all the bytes requested from a control if it can fit in less bytes. Eg: Returning 0xab instead of 0x00ab. usb 3-9: Failed to query (GET_DEF) UVC control 3 on unit 2: 1 (exp. 2).
Extend the returned value from the camera and return it.
Cc: stable@vger.kernel.org Fixes: a763b9fb58be ("media: uvcvideo: Do not return positive errors in uvc_query_ctrl()") Reviewed-by: Hans de Goede hdegoede@redhat.com Signed-off-by: Ricardo Ribalda ribalda@chromium.org
Reviewed-by: Laurent Pinchart laurent.pinchart@ideasonboard.com
drivers/media/usb/uvc/uvc_video.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)
diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c index cd9c29532fb0..67f714bca417 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -79,6 +79,27 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit, if (likely(ret == size)) return 0;
- /*
* Some devices return shorter USB control packets than expected if the* returned value can fit in less bytes. Zero all the bytes that the* device has not written.** This quirk is applied to all controls, regardless of their data type.* Most controls are little-endian integers, in which case the missing* bytes become 0 MSBs. For other data types, a different heuristic* could be implemented if a device is found needing it.** We exclude UVC_GET_INFO from the quirk. UVC_GET_LEN does not need* to be excluded because its size is always 1.*/- if (ret > 0 && query != UVC_GET_INFO) {
memset(data + ret, 0, size - ret);dev_warn_once(&dev->udev->dev,"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;- }
- if (ret != -EPIPE) { dev_err(&dev->udev->dev, "Failed to query (%s) UVC control %u on unit %u: %d (exp. %u).\n",
Hi,
On 28-Nov-24 9:53 PM, Ricardo Ribalda wrote:
Some cameras do not return all the bytes requested from a control if it can fit in less bytes. Eg: returning 0xab instead of 0x00ab. Support these devices.
Also, now that we are at it, improve uvc_query_ctrl() logging.
Signed-off-by: Ricardo Ribalda ribalda@chromium.org
Thank you for the new version, I've replaced the 2 patches in: https://gitlab.freedesktop.org/linux-media/users/uvc/-/commits/next/
with this new version.
Regards,
Hans
Changes in v5:
- Improve comment.
- Link to v4: https://lore.kernel.org/r/20241120-uvc-readless-v4-0-4672dbef3d46@chromium.o...
Changes in v4:
- Improve comment.
- Keep old likely(ret == size)
- Link to v3: https://lore.kernel.org/r/20241118-uvc-readless-v3-0-d97c1a3084d0@chromium.o...
Changes in v3:
- Improve documentation.
- Do not change return sequence.
- Use dev_ratelimit and dev_warn_once
- Link to v2: https://lore.kernel.org/r/20241008-uvc-readless-v2-0-04d9d51aee56@chromium.o...
Changes in v2:
- Rewrite error handling (Thanks Sakari)
- Discard 2/3. It is not needed after rewriting the error handling.
- Link to v1: https://lore.kernel.org/r/20241008-uvc-readless-v1-0-042ac4581f44@chromium.o...
Ricardo Ribalda (2): media: uvcvideo: Support partial control reads media: uvcvideo: Add more logging to uvc_query_ctrl()
drivers/media/usb/uvc/uvc_video.c | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-)
base-commit: 9852d85ec9d492ebef56dc5f229416c925758edc change-id: 20241008-uvc-readless-23f9b8cad0b3
Best regards,
linux-stable-mirror@lists.linaro.org
-
Hans de Goede -
Laurent Pinchart -
Ricardo Ribalda