Messages in this thread Patch in this message | | | From | Ricardo Ribalda <> | Subject | [PATCH v7 14/17] media: docs: Document the behaviour of uvcdriver | Date | Thu, 18 Mar 2021 21:29:25 +0100 |
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The uvc driver relies on the camera firmware to keep the control states and therefore is not capable of changing an inactive control.
Allow returning -EACESS in those cases.
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org> --- Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst | 5 +++++ Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst | 5 +++++ 2 files changed, 10 insertions(+)
diff --git a/Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst b/Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst index 4f1bed53fad5..8c0a203385c2 100644 --- a/Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst +++ b/Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst @@ -95,3 +95,8 @@ EBUSY EACCES Attempt to set a read-only control or to get a write-only control. + + Or if there is an attempt to set an inactive control and the driver is + not capable of keeping the new value until the control is active again. + This is the case for drivers that do not use the standard control + framework and rely purely on the hardware to keep the controls' state. diff --git a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst index b9c62affbb5a..bb7de7a25241 100644 --- a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst +++ b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst @@ -438,3 +438,8 @@ EACCES Or the ``which`` field was set to ``V4L2_CTRL_WHICH_REQUEST_VAL`` but the device does not support requests. + + Or if there is an attempt to set an inactive control and the driver is + not capable of keeping the new value until the control is active again. + This is the case for drivers that do not use the standard control + framework and rely purely on the hardware to keep the controls' state. -- 2.31.0.rc2.261.g7f71774620-goog
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