libcamera: media_device: Handle media device fd in acquire() and release()

To gain better control of when a file descriptor is open to the media
device and reduce the work needed in pipeline handler implementations,
handle the file descriptor in acquire() and release().

This changes the current behavior where a file descriptor is only open
when requested by the pipeline handler to that one is always open as
long a media device is acquired. This new behavior is desired to allow
implementing exclusive access to a pipeline handler between processes.

Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libcamera/include/media_device.h b/src/libcamera/include/media_device.h
index 9f038093..88398505 100644
--- a/src/libcamera/include/media_device.h
+++ b/src/libcamera/include/media_device.h
@@ -27,7 +27,7 @@ public:
 	~MediaDevice();
 
 	bool acquire();
-	void release() { acquired_ = false; }
+	void release();
 	bool busy() const { return acquired_; }
 
 	int open();