[PATCH 3/5] libcamera: software_isp: Handle queued input buffers on stop

[Milan Zamazal]

When SoftwareIsp stops, input and output buffers queued to it may not
yet be fully processed.  They will be eventually returned but stop means
stop, there should be no processing related actions invoked afterwards.

Let's stop forwarding processed input buffers from SoftwareIsp slots
when SoftwareIsp is stopped.  Let's track the queued input buffers and
return them back for capture in SoftwareIsp::stop().

Signed-off-by: Milan Zamazal <mzamazal at redhat.com>
---
 .../internal/software_isp/software_isp.h         |  1 +
 src/libcamera/software_isp/software_isp.cpp      | 16 +++++++++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/include/libcamera/internal/software_isp/software_isp.h b/include/libcamera/internal/software_isp/software_isp.h
index f2344355..bfe34725 100644
--- a/include/libcamera/internal/software_isp/software_isp.h
+++ b/include/libcamera/internal/software_isp/software_isp.h
@@ -102,6 +102,7 @@ private:
 	std::unique_ptr<ipa::soft::IPAProxySoft> ipa_;
 	bool running_;
 	std::deque<FrameBuffer *> queuedOutputBuffers_;
+	std::deque<FrameBuffer *> queuedInputBuffers_;
 };
 
 } /* namespace libcamera */
diff --git a/src/libcamera/software_isp/software_isp.cpp b/src/libcamera/software_isp/software_isp.cpp
index 4339e547..3a605ab2 100644
--- a/src/libcamera/software_isp/software_isp.cpp
+++ b/src/libcamera/software_isp/software_isp.cpp
@@ -301,6 +301,8 @@ int SoftwareIsp::queueBuffers(uint32_t frame, FrameBuffer *input,
 			return -EINVAL;
 	}
 
+	queuedInputBuffers_.push_back(input);
+
 	for (auto iter = outputs.begin(); iter != outputs.end(); iter++) {
 		FrameBuffer *const buffer = iter->second;
 		queuedOutputBuffers_.push_back(buffer);
@@ -327,6 +329,9 @@ int SoftwareIsp::start()
 
 /**
  * \brief Stops the Software ISP streaming operation
+ *
+ * All pending buffers are returned back (output buffers as canceled) before
+ * this method finishes.
  */
 void SoftwareIsp::stop()
 {
@@ -342,6 +347,10 @@ void SoftwareIsp::stop()
 		outputBufferReady.emit(buffer);
 	}
 	queuedOutputBuffers_.clear();
+
+	for (auto buffer : queuedInputBuffers_)
+		inputBufferReady.emit(buffer);
+	queuedInputBuffers_.clear();
 }
 
 /**
@@ -375,7 +384,12 @@ void SoftwareIsp::statsReady(uint32_t frame, uint32_t bufferId)
 
 void SoftwareIsp::inputReady(FrameBuffer *input)
 {
-	inputBufferReady.emit(input);
+	if (running_) {
+		queuedInputBuffers_.erase(find(queuedInputBuffers_.begin(),
+					       queuedInputBuffers_.end(),
+					       input));
+		inputBufferReady.emit(input);
+	}
 }
 
 void SoftwareIsp::outputReady(FrameBuffer *output)
-- 
2.48.1