libcamera: pipeline_handler: Cancel Request on queueing failure

Capture requests are queued by the PipelineHandler base class to each
pipeline handler implementation using the virtual queueRequestDevice()
function.

However, if the pipeline handler fails to queue the request to the
hardware, the request gets silently deleted from the list of queued
ones, without notifying application of the error.

Reporting to applications that a Request has failed to queue by
cancelling and then completing it allows applications to maintain their
request-tracking mechanism consistent with the one internal to the library.

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

1 files changed, 6 insertions, 2 deletions

diff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp
index f41b7a7b..e507a8bb 100644
--- a/src/libcamera/pipeline_handler.cpp
+++ b/src/libcamera/pipeline_handler.cpp
@@ -391,6 +391,8 @@ bool PipelineHandler::hasPendingRequests(const Camera *camera) const
  * This method queues a capture request to the pipeline handler for processing.
  * The request is first added to the internal list of queued requests, and
  * then passed to the pipeline handler with a call to queueRequestDevice().
+ * If the pipeline handler fails in queuing the request to the hardware the
+ * request is cancelled.
  *
  * Keeping track of queued requests ensures automatic completion of all requests
  * when the pipeline handler is stopped with stop(). Request completion shall be
@@ -409,8 +411,10 @@ void PipelineHandler::queueRequest(Request *request)
 	request->sequence_ = data->requestSequence_++;
 
 	int ret = queueRequestDevice(camera, request);
-	if (ret)
-		data->queuedRequests_.remove(request);
+	if (ret) {
+		request->cancel();
+		completeRequest(request);
+	}
 }
 
 /**