[PATCH v7 2/7] libcamera: Remove PipelineHandler Fatal check of non-empty MediaDevices

[Harvey Yang]

The Fatal check of having at least one MediaDevice was to prevent
pipeline handler implementations searching and owning media devices with
custom conventions, instead of using the base function
|acquireMediaDevice|. It also has the assumption that there's at least
one media device to make a camera work.

Now that the assumption will be broken by the virtual pipeline handler
added in the following patches, and developers should be aware of the
available functions in the base class to handle media devices, the Fatal
check is no longer needed.

Signed-off-by: Harvey Yang <chenghaoyang at chromium.org>
---
 src/libcamera/pipeline_handler.cpp | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp
index 5ea2ca78..125cf9d5 100644
--- a/src/libcamera/pipeline_handler.cpp
+++ b/src/libcamera/pipeline_handler.cpp
@@ -605,9 +605,14 @@ void PipelineHandler::registerCamera(std::shared_ptr<Camera> camera)
 {
 	cameras_.push_back(camera);
 
-	if (mediaDevices_.empty())
-		LOG(Pipeline, Fatal)
-			<< "Registering camera with no media devices!";
+	if (mediaDevices_.empty()) {
+		/*
+		 * For virtual devices with no MediaDevice, there are no system
+		 * devices to register.
+		 */
+		manager_->_d()->addCamera(std::move(camera));
+		return;
+	}
 
 	/*
 	 * Walk the entity list and map the devnums of all capture video nodes
-- 
2.46.0.rc1.232.g9752f9e123-goog