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| author | Hans de Goede <hdegoede@redhat.com> | 2024-08-30 13:12:05 +0200 |
|---|---|---|
| committer | Laurent Pinchart <laurent.pinchart@ideasonboard.com> | 2024-08-30 15:15:06 +0300 |
| commit | c05e45ac7743c60a78ebee1b9e341fa5e089285d (patch) | |
| tree | 3d9ca04258a7bfe54dadb46fd4a436ab35c4dc4c /test/mapped-buffer.cpp | |
| parent | 9020c2eec9de5d9b5bc1016b26e714b1c0206441 (diff) | |
pipeline_handler: Add acquireDevice() function to mirror releaseDevice()
libcamera always keeps all /dev/video# and /dev/v4l2_subdev# nodes for a
pipeline open after enumerating the camera.
This is a problem for the uvcvideo pipeline handler. Keeping /dev/video#
open stops the UVC USB device from being able to enter runtime-suspend
causing significant unnecessary power-usage.
Add a stub acquireDevice() function to the PipelineHandler class which
pipeline handlers can override.
The uvcvideo pipeline handler will use this to delay opening /dev/video#
until the device is acquired. This is a special case because the kernel
uvcvideo driver powers on the USB device as soon as /dev/video# is
opened. This behavior should *not* be copied by other pipeline handlers.
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Harvey Yang <chenghaoyang@chromium.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Diffstat (limited to 'test/mapped-buffer.cpp')
0 files changed, 0 insertions, 0 deletions