Ricardo Ribalda a03e32e601 media: uvcvideo: Turn on the camera if V4L2_EVENT_SUB_FL_SEND_INITIAL
If we subscribe to an event with V4L2_EVENT_SUB_FL_SEND_INITIAL, the
driver needs to report back some values that require the camera to be
powered on. But VIDIOC_SUBSCRIBE_EVENT is not part of the ioctls that
turn on the camera.

We could unconditionally turn on the camera during
VIDIOC_SUBSCRIBE_EVENT, but it is more efficient to turn it on only
during V4L2_EVENT_SUB_FL_SEND_INITIAL, which we believe is not a common
usecase.

To avoid a list_del if uvc_pm_get() fails, we move list_add_tail to the
end of the function.

Reviewed-by: Hans de Goede <hansg@kernel.org>
Fixes: d1b618e795 ("media: uvcvideo: Do not turn on the camera for some ioctls")
Cc: stable@vger.kernel.org
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Link: https://lore.kernel.org/r/20250701-uvc-grannular-invert-v4-5-8003b9b89f68@chromium.org
Signed-off-by: Hans de Goede <hansg@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
2025-07-11 19:27:28 +02:00
2025-02-19 14:53:27 -07:00
2025-07-10 11:32:26 +02:00
2025-06-08 13:44:43 -07:00
2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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