pipeline: uvcvideo: Implement acquireDevice() + releaseDevice()

The uvcvideo pipeline handler always keeps the uvcvideo /dev/video# node
for a pipeline open after enumerating the camera.

This is a problem for uvcvideo, as keeping the /dev/video# node open
stops the underlying USB device and the USB bus controller from being
able to enter runtime-suspend causing significant unnecessary
power-usage.

Implement acquireDevice() + releaseDevice(), openening /dev/video# on
acquire and closing it on release to fix this.

And make validate do a local video_->open() + close() around validate()
when not open yet, to keep validate() working on unacquired cameras.

Bug: https://bugs.libcamera.org/show_bug.cgi?id=168
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

0 files changed, 0 insertions, 0 deletions