[libcamera-devel] [PATCH v9 10/18] libcamera: stream: Remove bufferCount

Paul Elder paul.elder at ideasonboard.com
Fri Dec 16 13:29:31 CET 2022


From: Nícolas F. R. A. Prado <nfraprado at collabora.com>

Now that the number of buffers allocated by the FrameBufferAllocator
helper is passed through FrameBufferAllocator::allocate() and the
pipelines no longer use bufferCount for internal buffer or V4L2 buffer
slots allocation, we no longer need to have bufferCount in the
StreamConfiguration, so remove it.

Signed-off-by: Nícolas F. R. A. Prado <nfraprado at collabora.com>
Reviewed-by: Paul Elder <paul.elder at ideasonboard.com>
Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>

---
Changes in v9:
- rebased

Changes in v8:
- Updated the pipeline-handler guide to use MinimumRequests instead of
  bufferCount
- Removed kNumInternalBuffers as it was unused

Changes in v6:
- Removed IPU3_BUFFER_COUNT as it was unused
---
 Documentation/guides/pipeline-handler.rst         | 15 +++++++++------
 .../internal/converter/converter_v4l2_m2m.h       |  3 ---
 include/libcamera/stream.h                        |  2 --
 src/android/camera_stream.cpp                     |  2 +-
 src/libcamera/converter/converter_v4l2_m2m.cpp    |  3 ---
 src/libcamera/pipeline/ipu3/cio2.cpp              |  1 -
 src/libcamera/pipeline/ipu3/ipu3.cpp              |  8 --------
 .../pipeline/raspberrypi/raspberrypi.cpp          |  6 ------
 src/libcamera/pipeline/rkisp1/rkisp1_path.cpp     |  2 --
 src/libcamera/pipeline/rkisp1/rkisp1_path.h       |  2 --
 src/libcamera/pipeline/simple/simple.cpp          |  6 +-----
 src/libcamera/pipeline/uvcvideo/uvcvideo.cpp      |  3 ---
 src/libcamera/pipeline/vimc/vimc.cpp              |  3 ---
 src/libcamera/stream.cpp                          | 12 +++---------
 test/camera/buffer_import.cpp                     | 11 ++++++++---
 test/libtest/buffer_source.cpp                    |  4 ++--
 test/libtest/buffer_source.h                      |  2 +-
 test/v4l2_videodevice/buffer_cache.cpp            |  3 +--
 18 files changed, 26 insertions(+), 62 deletions(-)

diff --git a/Documentation/guides/pipeline-handler.rst b/Documentation/guides/pipeline-handler.rst
index 70de82af..1d4314bb 100644
--- a/Documentation/guides/pipeline-handler.rst
+++ b/Documentation/guides/pipeline-handler.rst
@@ -827,14 +827,12 @@ As well as a list of supported StreamFormats, the StreamConfiguration is also
 expected to provide an initialised default configuration. This may be arbitrary,
 but depending on use case you may wish to select an output that matches the
 Sensor output, or prefer a pixelformat which might provide higher performance on
-the hardware. The bufferCount represents the number of buffers required to
-support functional continuous processing on this stream.
+the hardware.
 
 .. code-block:: cpp
 
    cfg.pixelFormat = formats::BGR888;
    cfg.size = { 1280, 720 };
-   cfg.bufferCount = 4;
 
 Finally add each ``StreamConfiguration`` generated to the
 ``CameraConfiguration``, and ensure that it has been validated before returning
@@ -900,8 +898,6 @@ Add the following function implementation to your file:
                   status = Adjusted;
            }
 
-           cfg.bufferCount = 4;
-
            return status;
    }
 
@@ -1145,13 +1141,20 @@ is performed by using the ``V4L2VideoDevice`` API, which provides an
 
 .. _FrameBuffer: https://libcamera.org/api-html/classlibcamera_1_1FrameBuffer.html
 
+The number passed to ``importBuffers()`` should be at least equal to the value
+of the ``MinimumRequests`` property in order to be possible to queue enough
+buffers to the video device that frames won't be dropped during capture. A
+bigger value can be advantageous to reduce the thrashing of dma-buf file
+descriptor mappings in case the application queues more requests and therefore
+improve performance, but for simplicity we'll just use ``MinimumRequests``.
+
 Implement the pipeline handler ``start()`` function by replacing the stub
 version with the following code:
 
 .. code-block:: c++
 
    VividCameraData *data = cameraData(camera);
-   unsigned int count = data->stream_.configuration().bufferCount;
+   unsigned int count = camera->properties().get(properties::MinimumRequests);
 
    int ret = data->video_->importBuffers(count);
    if (ret < 0)
diff --git a/include/libcamera/internal/converter/converter_v4l2_m2m.h b/include/libcamera/internal/converter/converter_v4l2_m2m.h
index 1f471071..bcc03347 100644
--- a/include/libcamera/internal/converter/converter_v4l2_m2m.h
+++ b/include/libcamera/internal/converter/converter_v4l2_m2m.h
@@ -86,9 +86,6 @@ private:
 		V4L2M2MConverter *converter_;
 		unsigned int index_;
 		std::unique_ptr<V4L2M2MDevice> m2m_;
-
-		unsigned int inputBufferCount_;
-		unsigned int outputBufferCount_;
 	};
 
 	std::unique_ptr<V4L2M2MDevice> m2m_;
diff --git a/include/libcamera/stream.h b/include/libcamera/stream.h
index 29235ddf..dba9b453 100644
--- a/include/libcamera/stream.h
+++ b/include/libcamera/stream.h
@@ -47,8 +47,6 @@ struct StreamConfiguration {
 	unsigned int stride;
 	unsigned int frameSize;
 
-	unsigned int bufferCount;
-
 	std::optional<ColorSpace> colorSpace;
 
 	Stream *stream() const { return stream_; }
diff --git a/src/android/camera_stream.cpp b/src/android/camera_stream.cpp
index 045e6006..f51f0c3a 100644
--- a/src/android/camera_stream.cpp
+++ b/src/android/camera_stream.cpp
@@ -131,7 +131,7 @@ int CameraStream::configure()
 	allocator_ = std::make_unique<PlatformFrameBufferAllocator>(cameraDevice_);
 	mutex_ = std::make_unique<Mutex>();
 
-	camera3Stream_->max_buffers = configuration().bufferCount;
+	camera3Stream_->max_buffers = bufferCount;
 
 	return 0;
 }
diff --git a/src/libcamera/converter/converter_v4l2_m2m.cpp b/src/libcamera/converter/converter_v4l2_m2m.cpp
index 9d25f25a..b9372804 100644
--- a/src/libcamera/converter/converter_v4l2_m2m.cpp
+++ b/src/libcamera/converter/converter_v4l2_m2m.cpp
@@ -95,9 +95,6 @@ int V4L2M2MConverter::Stream::configure(const StreamConfiguration &inputCfg,
 		return -EINVAL;
 	}
 
-	inputBufferCount_ = inputCfg.bufferCount;
-	outputBufferCount_ = outputCfg.bufferCount;
-
 	return 0;
 }
 
diff --git a/src/libcamera/pipeline/ipu3/cio2.cpp b/src/libcamera/pipeline/ipu3/cio2.cpp
index feb69991..02dc9406 100644
--- a/src/libcamera/pipeline/ipu3/cio2.cpp
+++ b/src/libcamera/pipeline/ipu3/cio2.cpp
@@ -234,7 +234,6 @@ StreamConfiguration CIO2Device::generateConfiguration(Size size) const
 
 	cfg.size = sensorFormat.size;
 	cfg.pixelFormat = mbusCodesToPixelFormat.at(sensorFormat.mbus_code);
-	cfg.bufferCount = kBufferCount;
 
 	return cfg;
 }
diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
index 4d8fcfeb..4511adde 100644
--- a/src/libcamera/pipeline/ipu3/ipu3.cpp
+++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
@@ -98,7 +98,6 @@ private:
 class IPU3CameraConfiguration : public CameraConfiguration
 {
 public:
-	static constexpr unsigned int kBufferCount = 4;
 	static constexpr unsigned int kMaxStreams = 3;
 
 	IPU3CameraConfiguration(IPU3CameraData *data);
@@ -326,7 +325,6 @@ CameraConfiguration::Status IPU3CameraConfiguration::validate()
 			/* Initialize the RAW stream with the CIO2 configuration. */
 			cfg->size = cio2Configuration_.size;
 			cfg->pixelFormat = cio2Configuration_.pixelFormat;
-			cfg->bufferCount = cio2Configuration_.bufferCount;
 			cfg->stride = info.stride(cfg->size.width, 0, 64);
 			cfg->frameSize = info.frameSize(cfg->size, 64);
 			cfg->setStream(const_cast<Stream *>(&data_->rawStream_));
@@ -370,7 +368,6 @@ CameraConfiguration::Status IPU3CameraConfiguration::validate()
 					      ImgUDevice::kOutputAlignHeight);
 
 			cfg->pixelFormat = formats::NV12;
-			cfg->bufferCount = kBufferCount;
 			cfg->stride = info.stride(cfg->size.width, 0, 1);
 			cfg->frameSize = info.frameSize(cfg->size, 1);
 
@@ -439,7 +436,6 @@ PipelineHandlerIPU3::generateConfiguration(Camera *camera, const StreamRoles &ro
 	Size sensorResolution = data->cio2_.sensor()->resolution();
 	for (const StreamRole role : roles) {
 		std::map<PixelFormat, std::vector<SizeRange>> streamFormats;
-		unsigned int bufferCount;
 		PixelFormat pixelFormat;
 		Size size;
 
@@ -459,7 +455,6 @@ PipelineHandlerIPU3::generateConfiguration(Camera *camera, const StreamRoles &ro
 					       .alignedDownTo(ImgUDevice::kOutputMarginWidth,
 							      ImgUDevice::kOutputMarginHeight);
 			pixelFormat = formats::NV12;
-			bufferCount = IPU3CameraConfiguration::kBufferCount;
 			streamFormats[pixelFormat] = { { ImgUDevice::kOutputMinSize, size } };
 
 			break;
@@ -469,7 +464,6 @@ PipelineHandlerIPU3::generateConfiguration(Camera *camera, const StreamRoles &ro
 				data->cio2_.generateConfiguration(sensorResolution);
 			pixelFormat = cio2Config.pixelFormat;
 			size = cio2Config.size;
-			bufferCount = cio2Config.bufferCount;
 
 			for (const PixelFormat &format : data->cio2_.formats())
 				streamFormats[format] = data->cio2_.sizes(format);
@@ -488,7 +482,6 @@ PipelineHandlerIPU3::generateConfiguration(Camera *camera, const StreamRoles &ro
 					       .alignedDownTo(ImgUDevice::kOutputAlignWidth,
 							      ImgUDevice::kOutputAlignHeight);
 			pixelFormat = formats::NV12;
-			bufferCount = IPU3CameraConfiguration::kBufferCount;
 			streamFormats[pixelFormat] = { { ImgUDevice::kOutputMinSize, size } };
 
 			break;
@@ -504,7 +497,6 @@ PipelineHandlerIPU3::generateConfiguration(Camera *camera, const StreamRoles &ro
 		StreamConfiguration cfg(formats);
 		cfg.size = size;
 		cfg.pixelFormat = pixelFormat;
-		cfg.bufferCount = bufferCount;
 		config->addConfiguration(cfg);
 	}
 
diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
index 72502c36..c0d96024 100644
--- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
+++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
@@ -591,7 +591,6 @@ PipelineHandlerRPi::generateConfiguration(Camera *camera, const StreamRoles &rol
 	std::unique_ptr<CameraConfiguration> config =
 		std::make_unique<RPiCameraConfiguration>(data);
 	V4L2SubdeviceFormat sensorFormat;
-	unsigned int bufferCount;
 	PixelFormat pixelFormat;
 	V4L2VideoDevice::Formats fmts;
 	Size size;
@@ -612,7 +611,6 @@ PipelineHandlerRPi::generateConfiguration(Camera *camera, const StreamRoles &rol
 							    BayerFormat::Packing::CSI2);
 			ASSERT(pixelFormat.isValid());
 			colorSpace = ColorSpace::Raw;
-			bufferCount = 2;
 			rawCount++;
 			break;
 
@@ -627,7 +625,6 @@ PipelineHandlerRPi::generateConfiguration(Camera *camera, const StreamRoles &rol
 			colorSpace = ColorSpace::Sycc;
 			/* Return the largest sensor resolution. */
 			size = sensorSize;
-			bufferCount = 1;
 			outCount++;
 			break;
 
@@ -648,7 +645,6 @@ PipelineHandlerRPi::generateConfiguration(Camera *camera, const StreamRoles &rol
 			 */
 			colorSpace = ColorSpace::Rec709;
 			size = { 1920, 1080 };
-			bufferCount = 4;
 			outCount++;
 			break;
 
@@ -657,7 +653,6 @@ PipelineHandlerRPi::generateConfiguration(Camera *camera, const StreamRoles &rol
 			pixelFormat = formats::ARGB8888;
 			colorSpace = ColorSpace::Sycc;
 			size = { 800, 600 };
-			bufferCount = 4;
 			outCount++;
 			break;
 
@@ -704,7 +699,6 @@ PipelineHandlerRPi::generateConfiguration(Camera *camera, const StreamRoles &rol
 		cfg.size = size;
 		cfg.pixelFormat = pixelFormat;
 		cfg.colorSpace = colorSpace;
-		cfg.bufferCount = bufferCount;
 		config->addConfiguration(cfg);
 	}
 
diff --git a/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp b/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp
index a168e0ad..9ef9c3e2 100644
--- a/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp
+++ b/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp
@@ -190,7 +190,6 @@ RkISP1Path::generateConfiguration(const CameraSensor *sensor, StreamRole role)
 	StreamConfiguration cfg(formats);
 	cfg.pixelFormat = format;
 	cfg.size = maxResolution;
-	cfg.bufferCount = RKISP1_BUFFER_COUNT;
 
 	return cfg;
 }
@@ -280,7 +279,6 @@ CameraConfiguration::Status RkISP1Path::validate(const CameraSensor *sensor,
 
 	cfg->size.boundTo(maxResolution);
 	cfg->size.expandTo(minResolution);
-	cfg->bufferCount = RKISP1_BUFFER_COUNT;
 
 	V4L2DeviceFormat format;
 	format.fourcc = video_->toV4L2PixelFormat(cfg->pixelFormat);
diff --git a/src/libcamera/pipeline/rkisp1/rkisp1_path.h b/src/libcamera/pipeline/rkisp1/rkisp1_path.h
index 5b53783c..366720de 100644
--- a/src/libcamera/pipeline/rkisp1/rkisp1_path.h
+++ b/src/libcamera/pipeline/rkisp1/rkisp1_path.h
@@ -63,8 +63,6 @@ public:
 private:
 	void populateFormats();
 
-	static constexpr unsigned int RKISP1_BUFFER_COUNT = 4;
-
 	const char *name_;
 	bool running_;
 
diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
index 196e5252..5d309777 100644
--- a/src/libcamera/pipeline/simple/simple.cpp
+++ b/src/libcamera/pipeline/simple/simple.cpp
@@ -338,7 +338,6 @@ protected:
 	int queueRequestDevice(Camera *camera, Request *request) override;
 
 private:
-	static constexpr unsigned int kNumInternalBuffers = 3;
 	static constexpr unsigned int kSimpleBufferSlotCount = 16;
 
 	struct EntityData {
@@ -1010,7 +1009,7 @@ CameraConfiguration::Status SimpleCameraConfiguration::validate()
 		    cfg.size != pipeConfig_->captureSize)
 			needConversion_ = true;
 
-		/* Set the stride, frameSize and bufferCount. */
+		/* Set the stride and frameSize. */
 		if (needConversion_) {
 			std::tie(cfg.stride, cfg.frameSize) =
 				data_->converter_->strideAndFrameSize(cfg.pixelFormat,
@@ -1029,8 +1028,6 @@ CameraConfiguration::Status SimpleCameraConfiguration::validate()
 			cfg.stride = format.planes[0].bpl;
 			cfg.frameSize = format.planes[0].size;
 		}
-
-		cfg.bufferCount = 3;
 	}
 
 	return status;
@@ -1174,7 +1171,6 @@ int SimplePipelineHandler::configure(Camera *camera, CameraConfiguration *c)
 	inputCfg.pixelFormat = pipeConfig->captureFormat;
 	inputCfg.size = pipeConfig->captureSize;
 	inputCfg.stride = captureFormat.planes[0].bpl;
-	inputCfg.bufferCount = kNumInternalBuffers;
 
 	/* Set the MinimumRequests property. */
 	unsigned int minimumRequests;
diff --git a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
index 18966d01..5d88e6f3 100644
--- a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
+++ b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
@@ -154,8 +154,6 @@ CameraConfiguration::Status UVCCameraConfiguration::validate()
 		status = Adjusted;
 	}
 
-	cfg.bufferCount = 4;
-
 	V4L2DeviceFormat format;
 	format.fourcc = data_->video_->toV4L2PixelFormat(cfg.pixelFormat);
 	format.size = cfg.size;
@@ -196,7 +194,6 @@ PipelineHandlerUVC::generateConfiguration(Camera *camera,
 
 	cfg.pixelFormat = formats.pixelformats().front();
 	cfg.size = formats.sizes(cfg.pixelFormat).back();
-	cfg.bufferCount = 4;
 
 	config->addConfiguration(cfg);
 
diff --git a/src/libcamera/pipeline/vimc/vimc.cpp b/src/libcamera/pipeline/vimc/vimc.cpp
index eaa6ebf7..ef5146f9 100644
--- a/src/libcamera/pipeline/vimc/vimc.cpp
+++ b/src/libcamera/pipeline/vimc/vimc.cpp
@@ -171,8 +171,6 @@ CameraConfiguration::Status VimcCameraConfiguration::validate()
 		status = Adjusted;
 	}
 
-	cfg.bufferCount = 4;
-
 	V4L2DeviceFormat format;
 	format.fourcc = data_->video_->toV4L2PixelFormat(cfg.pixelFormat);
 	format.size = cfg.size;
@@ -230,7 +228,6 @@ PipelineHandlerVimc::generateConfiguration(Camera *camera,
 
 	cfg.pixelFormat = formats::BGR888;
 	cfg.size = { 1920, 1080 };
-	cfg.bufferCount = 4;
 
 	config->addConfiguration(cfg);
 
diff --git a/src/libcamera/stream.cpp b/src/libcamera/stream.cpp
index 67f30815..aa61c855 100644
--- a/src/libcamera/stream.cpp
+++ b/src/libcamera/stream.cpp
@@ -280,8 +280,7 @@ SizeRange StreamFormats::range(const PixelFormat &pixelformat) const
  * handlers provide StreamFormats.
  */
 StreamConfiguration::StreamConfiguration()
-	: pixelFormat(0), stride(0), frameSize(0), bufferCount(0),
-	  stream_(nullptr)
+	: pixelFormat(0), stride(0), frameSize(0), stream_(nullptr)
 {
 }
 
@@ -289,8 +288,8 @@ StreamConfiguration::StreamConfiguration()
  * \brief Construct a configuration with stream formats
  */
 StreamConfiguration::StreamConfiguration(const StreamFormats &formats)
-	: pixelFormat(0), stride(0), frameSize(0), bufferCount(0),
-	  stream_(nullptr), formats_(formats)
+	: pixelFormat(0), stride(0), frameSize(0), stream_(nullptr),
+	  formats_(formats)
 {
 }
 
@@ -324,11 +323,6 @@ StreamConfiguration::StreamConfiguration(const StreamFormats &formats)
  * validating the configuration with a call to CameraConfiguration::validate().
  */
 
-/**
- * \var StreamConfiguration::bufferCount
- * \brief Requested number of buffers to allocate for the stream
- */
-
 /**
  * \var StreamConfiguration::colorSpace
  * \brief The ColorSpace for this stream
diff --git a/test/camera/buffer_import.cpp b/test/camera/buffer_import.cpp
index 92884004..cb7a0cef 100644
--- a/test/camera/buffer_import.cpp
+++ b/test/camera/buffer_import.cpp
@@ -16,6 +16,8 @@
 #include <libcamera/base/thread.h>
 #include <libcamera/base/timer.h>
 
+#include <libcamera/property_ids.h>
+
 #include "libcamera/internal/device_enumerator.h"
 #include "libcamera/internal/media_device.h"
 #include "libcamera/internal/v4l2_videodevice.h"
@@ -93,10 +95,13 @@ protected:
 			return TestFail;
 		}
 
+		unsigned int bufferCount =
+			camera_->properties().get(properties::MinimumRequests).value();
+
 		Stream *stream = cfg.stream();
 
 		BufferSource source;
-		int ret = source.allocate(cfg);
+		int ret = source.allocate(cfg, bufferCount);
 		if (ret != TestPass)
 			return ret;
 
@@ -140,10 +145,10 @@ protected:
 		while (timer.isRunning())
 			dispatcher->processEvents();
 
-		if (completeRequestsCount_ < cfg.bufferCount * 2) {
+		if (completeRequestsCount_ < bufferCount * 2) {
 			std::cout << "Failed to capture enough frames (got "
 				  << completeRequestsCount_ << " expected at least "
-				  << cfg.bufferCount * 2 << ")" << std::endl;
+				  << bufferCount * 2 << ")" << std::endl;
 			return TestFail;
 		}
 
diff --git a/test/libtest/buffer_source.cpp b/test/libtest/buffer_source.cpp
index dde11f36..c1bc45db 100644
--- a/test/libtest/buffer_source.cpp
+++ b/test/libtest/buffer_source.cpp
@@ -26,7 +26,7 @@ BufferSource::~BufferSource()
 		media_->release();
 }
 
-int BufferSource::allocate(const StreamConfiguration &config)
+int BufferSource::allocate(const StreamConfiguration &config, unsigned int count)
 {
 	/* Locate and open the video device. */
 	std::string videoDeviceName = "vivid-000-vid-out";
@@ -78,7 +78,7 @@ int BufferSource::allocate(const StreamConfiguration &config)
 		return TestFail;
 	}
 
-	if (video->allocateBuffers(config.bufferCount, &buffers_) < 0) {
+	if (video->allocateBuffers(count, &buffers_) < 0) {
 		std::cout << "Failed to allocate buffers" << std::endl;
 		return TestFail;
 	}
diff --git a/test/libtest/buffer_source.h b/test/libtest/buffer_source.h
index 0cc71aa5..f430a7f3 100644
--- a/test/libtest/buffer_source.h
+++ b/test/libtest/buffer_source.h
@@ -18,7 +18,7 @@ public:
 	BufferSource();
 	~BufferSource();
 
-	int allocate(const libcamera::StreamConfiguration &config);
+	int allocate(const libcamera::StreamConfiguration &config, unsigned int count);
 	const std::vector<std::unique_ptr<libcamera::FrameBuffer>> &buffers();
 
 private:
diff --git a/test/v4l2_videodevice/buffer_cache.cpp b/test/v4l2_videodevice/buffer_cache.cpp
index 5a9aa219..8d2cf6d1 100644
--- a/test/v4l2_videodevice/buffer_cache.cpp
+++ b/test/v4l2_videodevice/buffer_cache.cpp
@@ -174,10 +174,9 @@ public:
 		StreamConfiguration cfg;
 		cfg.pixelFormat = formats::YUYV;
 		cfg.size = Size(600, 800);
-		cfg.bufferCount = numBuffers;
 
 		BufferSource source;
-		int ret = source.allocate(cfg);
+		int ret = source.allocate(cfg, numBuffers);
 		if (ret != TestPass)
 			return ret;
 
-- 
2.35.1



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