[libcamera-devel] [PATCH] v4l2: Extend device caps with V4L2_CAP_STREAMING

[Nicolas Dufresne]

From: Nicolas Dufresne <nicolas.dufresne at collabora.com>

This capability tells the application that mmap() is supported. GStreamer
would return an error saying there there is no input/output method supported
by this device otherwise. This was tested with:

LD_PRELOAD=$(pwd)/build/src/v4l2/v4l2-compat.so GST_DEBUG="v4l2*:7" gst-launch-1.0 v4l2src ! videoconvert ! autovideosink

With this patch, GStreamer will reach playing state. It then blocks waiting on
poll() which is not implemented yet on our side.

Signed-off-by: Nicolas Dufresne <nicolas.dufresne at collabora.com>
---
 src/v4l2/v4l2_camera_proxy.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp
index 3013a3d..e58fd6a 100644
--- a/src/v4l2/v4l2_camera_proxy.cpp
+++ b/src/v4l2/v4l2_camera_proxy.cpp
@@ -179,7 +179,7 @@ void V4L2CameraProxy::querycap(std::shared_ptr<Camera> camera)
 		       sizeof(capabilities_.bus_info));
 	/* \todo Put this in a header/config somewhere. */
 	capabilities_.version = KERNEL_VERSION(5, 2, 0);
-	capabilities_.device_caps = V4L2_CAP_VIDEO_CAPTURE;
+	capabilities_.device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING;
 	capabilities_.capabilities = capabilities_.device_caps
 				   | V4L2_CAP_DEVICE_CAPS;
 	memset(capabilities_.reserved, 0, sizeof(capabilities_.reserved));
-- 
2.24.1