[PATCH v8 17/19] media: docs: Document the behaviour of uvcdriver
From: Ricardo Ribalda <hidden>
Date: 2021-03-19 17:10:23
Also in:
lkml
Subsystem:
media input infrastructure (v4l/dvb), the rest · Maintainers:
Mauro Carvalho Chehab, Linus Torvalds
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 <redacted> --- 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