[PATCH v2 2/2] pipeline: simple: Fix matching with empty media graphs

[Paul Elder]

The match() function currently reports that it is not possible to create
any cameras if it encounters an empty media graph.

Fix this by looping over all media graphs and only returning false when
all of them fail to create a camera.

Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
---
Changes in v2:
- prevent a mix of valid and invalid media devices from ending up in
  mediaDevices_
---
 src/libcamera/pipeline/simple/simple.cpp | 52 ++++++++++++++++--------
 1 file changed, 35 insertions(+), 17 deletions(-)

diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
index 6e039bf35fc1..a6bdd6024a99 100644
--- a/src/libcamera/pipeline/simple/simple.cpp
+++ b/src/libcamera/pipeline/simple/simple.cpp
@@ -373,6 +373,9 @@ private:
 		return static_cast<SimpleCameraData *>(camera->_d());
 	}
 
+	bool matchDevice(MediaDevice *media, const SimplePipelineInfo &info,
+			 DeviceEnumerator *enumerator);
+
 	std::vector<MediaEntity *> locateSensors(MediaDevice *media);
 	static int resetRoutingTable(V4L2Subdevice *subdev);
 
@@ -1532,25 +1535,13 @@ int SimplePipelineHandler::resetRoutingTable(V4L2Subdevice *subdev)
 	return 0;
 }
 
-bool SimplePipelineHandler::match(DeviceEnumerator *enumerator)
+bool SimplePipelineHandler::matchDevice(MediaDevice *media,
+					const SimplePipelineInfo &info,
+					DeviceEnumerator *enumerator)
 {
-	const SimplePipelineInfo *info = nullptr;
 	unsigned int numStreams = 1;
-	MediaDevice *media;
-
-	for (const SimplePipelineInfo &inf : supportedDevices) {
-		DeviceMatch dm(inf.driver);
-		media = acquireMediaDevice(enumerator, dm);
-		if (media) {
-			info = &inf;
-			break;
-		}
-	}
-
-	if (!media)
-		return false;
 
-	for (const auto &[name, streams] : info->converters) {
+	for (const auto &[name, streams] : info.converters) {
 		DeviceMatch converterMatch(name);
 		converter_ = acquireMediaDevice(enumerator, converterMatch);
 		if (converter_) {
@@ -1559,7 +1550,7 @@ bool SimplePipelineHandler::match(DeviceEnumerator *enumerator)
 		}
 	}
 
-	swIspEnabled_ = info->swIspEnabled;
+	swIspEnabled_ = info.swIspEnabled;
 
 	/* Locate the sensors. */
 	std::vector<MediaEntity *> sensors = locateSensors(media);
@@ -1678,6 +1669,33 @@ bool SimplePipelineHandler::match(DeviceEnumerator *enumerator)
 	return registered;
 }
 
+bool SimplePipelineHandler::match(DeviceEnumerator *enumerator)
+{
+	MediaDevice *media;
+
+	for (const SimplePipelineInfo &inf : supportedDevices) {
+		DeviceMatch dm(inf.driver);
+		while ((media = acquireMediaDevice(enumerator, dm))) {
+			/*
+			 * If match succeeds, return true to let match() be
+			 * called again on a new instance of the pipeline
+			 * handler. Otherwise keep looping until we do
+			 * successfully match one (or run out).
+			 */
+			if (matchDevice(media, inf, enumerator)) {
+				LOG(SimplePipeline, Debug)
+					<< "Matched on device: "
+					<< media->deviceNode();
+				return true;
+			}
+		}
+
+		clearMediaDevices();
+	}
+
+	return false;
+}
+
 V4L2VideoDevice *SimplePipelineHandler::video(const MediaEntity *entity)
 {
 	auto iter = entities_.find(entity);
-- 
2.47.2