[libcamera-devel] [PATCH v2] android: camera_device: Stop camera when re-configuring it

[Jacopo Mondi]

The Android camera device HAL3 specification does not require a
camera to go through any explicit close() call between configurations.
It is legit for a camera to be configured, a number of requests
processed and the re-configured again without any explicit stop.

The libcamera Android camera HAL starts the Camera at the first handled
request, and only stops it at camera close time. This mean, that two
camera configuration attempts part of the same streaming session are only
interleaved by capture requests handling.

The libcamera::Camera state machine requires the Camera to be stopped,
before any configuration take place, and this currently doesn't happen.

Fix this by stopping the camera and the associated worker thread if
a configuration attempt is performed while the Camera is in running
state.

This patch fixes cros_camera_test:
Camera3PreviewTest/Camera3SinglePreviewTest.Camera3BasicPreviewTest/0

Reviewed-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>

---
v1 -> v2:
- Stop the camera at the very beginning of the configureStreams() function

---
 src/android/camera_device.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
index 675af5705055..dc711550546c 100644
--- a/src/android/camera_device.cpp
+++ b/src/android/camera_device.cpp
@@ -1210,6 +1210,13 @@ PixelFormat CameraDevice::toPixelFormat(int format) const
  */
 int CameraDevice::configureStreams(camera3_stream_configuration_t *stream_list)
 {
+	/* Before any configuration attempt, stop the camera if it's running. */
+	if (running_) {
+		worker_.stop();
+		camera_->stop();
+		running_ = false;
+	}
+
 	/*
 	 * Generate an empty configuration, and construct a StreamConfiguration
 	 * for each camera3_stream to add to it.
--
2.29.1