[libcamera-devel,v3,1/3] libcamera: pipeline: Pass libcamera controls into pipeline_handler::start()
diff mbox series

Message ID 20201204153121.66136-2-naush@raspberrypi.com
State Accepted
Headers show
Series
  • Pass controls on camera:start()
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Commit Message

Naushir Patuck Dec. 4, 2020, 3:31 p.m. UTC 
Applications now have the ability to pass in controls that need to be
applied on startup, rather than doing it through Request where there might
be some frames of delay in getting the controls applied.

This commit adds the ability to pass in a set of libcamera controls into
the pipeline handlers through the pipeline_handler::start() method. These
controls are provided by the application through the camera::start()
public API.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: David Plowman <david.plowman@raspberrypi.com>
Tested-by: David Plowman <david.plowman@raspberrypi.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
---
 Documentation/guides/pipeline-handler.rst          |  4 ++--
 include/libcamera/camera.h                         |  2 +-
 include/libcamera/internal/pipeline_handler.h      |  2 +-
 src/libcamera/camera.cpp                           | 11 ++++++-----
 src/libcamera/pipeline/ipu3/ipu3.cpp               |  4 ++--
 src/libcamera/pipeline/raspberrypi/raspberrypi.cpp |  4 ++--
 src/libcamera/pipeline/rkisp1/rkisp1.cpp           |  4 ++--
 src/libcamera/pipeline/simple/simple.cpp           |  4 ++--
 src/libcamera/pipeline/uvcvideo/uvcvideo.cpp       |  4 ++--
 src/libcamera/pipeline/vimc/vimc.cpp               |  4 ++--
 src/libcamera/pipeline_handler.cpp                 |  1 +
 11 files changed, 23 insertions(+), 21 deletions(-)

Comments

Laurent Pinchart Dec. 5, 2020, 9:07 p.m. UTC | #1 
Hi Naush,

Thank you for the patch.

On Fri, Dec 04, 2020 at 03:31:19PM +0000, Naushir Patuck wrote:
> Applications now have the ability to pass in controls that need to be
> applied on startup, rather than doing it through Request where there might
> be some frames of delay in getting the controls applied.
> 
> This commit adds the ability to pass in a set of libcamera controls into
> the pipeline handlers through the pipeline_handler::start() method. These
> controls are provided by the application through the camera::start()
> public API.
> 
> Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
> Reviewed-by: David Plowman <david.plowman@raspberrypi.com>
> Tested-by: David Plowman <david.plowman@raspberrypi.com>
> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
> ---
>  Documentation/guides/pipeline-handler.rst          |  4 ++--
>  include/libcamera/camera.h                         |  2 +-
>  include/libcamera/internal/pipeline_handler.h      |  2 +-
>  src/libcamera/camera.cpp                           | 11 ++++++-----
>  src/libcamera/pipeline/ipu3/ipu3.cpp               |  4 ++--
>  src/libcamera/pipeline/raspberrypi/raspberrypi.cpp |  4 ++--
>  src/libcamera/pipeline/rkisp1/rkisp1.cpp           |  4 ++--
>  src/libcamera/pipeline/simple/simple.cpp           |  4 ++--
>  src/libcamera/pipeline/uvcvideo/uvcvideo.cpp       |  4 ++--
>  src/libcamera/pipeline/vimc/vimc.cpp               |  4 ++--
>  src/libcamera/pipeline_handler.cpp                 |  1 +
>  11 files changed, 23 insertions(+), 21 deletions(-)
> 
> diff --git a/Documentation/guides/pipeline-handler.rst b/Documentation/guides/pipeline-handler.rst
> index 57aee455..63275a12 100644
> --- a/Documentation/guides/pipeline-handler.rst
> +++ b/Documentation/guides/pipeline-handler.rst
> @@ -209,7 +209,7 @@ methods for the overridden class members.
>            int exportFrameBuffers(Camera *camera, Stream *stream,
>            std::vector<std::unique_ptr<FrameBuffer>> *buffers) override;
>  
> -          int start(Camera *camera) override;
> +          int start(Camera *camera, ControlList *controls) override;
>            void stop(Camera *camera) override;
>  
>            int queueRequestDevice(Camera *camera, Request *request) override;
> @@ -239,7 +239,7 @@ methods for the overridden class members.
>            return -1;
>     }
>  
> -   int PipelineHandlerVivid::start(Camera *camera)
> +   int PipelineHandlerVivid::start(Camera *camera, ControlList *controls)
>     {
>            return -1;
>     }
> diff --git a/include/libcamera/camera.h b/include/libcamera/camera.h
> index 5c5f1a05..f94f8599 100644
> --- a/include/libcamera/camera.h
> +++ b/include/libcamera/camera.h
> @@ -103,7 +103,7 @@ public:
>  	std::unique_ptr<Request> createRequest(uint64_t cookie = 0);
>  	int queueRequest(Request *request);
>  
> -	int start();
> +	int start(ControlList *controls = nullptr);
>  	int stop();
>  
>  private:
> diff --git a/include/libcamera/internal/pipeline_handler.h b/include/libcamera/internal/pipeline_handler.h
> index c12c8904..bd3c4a81 100644
> --- a/include/libcamera/internal/pipeline_handler.h
> +++ b/include/libcamera/internal/pipeline_handler.h
> @@ -78,7 +78,7 @@ public:
>  	virtual int exportFrameBuffers(Camera *camera, Stream *stream,
>  				       std::vector<std::unique_ptr<FrameBuffer>> *buffers) = 0;
>  
> -	virtual int start(Camera *camera) = 0;
> +	virtual int start(Camera *camera, ControlList *controls) = 0;
>  	virtual void stop(Camera *camera) = 0;
>  
>  	int queueRequest(Camera *camera, Request *request);
> diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
> index bcb7b046..ffb63fb2 100644
> --- a/src/libcamera/camera.cpp
> +++ b/src/libcamera/camera.cpp
> @@ -1003,9 +1003,10 @@ int Camera::queueRequest(Request *request)
>  /**
>   * \brief Start capture from camera

Missing

 * \param[in] controls Controls to be applied before starting the Camera

>   *
> - * Start the camera capture session. Once the camera is started the application
> - * can queue requests to the camera to process and return to the application
> - * until the capture session is terminated with \a stop().
> + * Start the camera capture session, optionally providing a list of controls to
> + * action before starting. Once the camera is started the application can queue

s/action/apply/ ?

> + * requests to the camera to process and return to the application until the
> + * capture session is terminated with \a stop().
>   *
>   * \context This function may only be called when the camera is in the
>   * Configured state as defined in \ref camera_operation, and shall be
> @@ -1016,7 +1017,7 @@ int Camera::queueRequest(Request *request)
>   * \retval -ENODEV The camera has been disconnected from the system
>   * \retval -EACCES The camera is not in a state where it can be started
>   */
> -int Camera::start()
> +int Camera::start(ControlList *controls)
>  {
>  	Private *const d = LIBCAMERA_D_PTR();
>  
> @@ -1027,7 +1028,7 @@ int Camera::start()
>  	LOG(Camera, Debug) << "Starting capture";
>  
>  	ret = d->pipe_->invokeMethod(&PipelineHandler::start,
> -				     ConnectionTypeBlocking, this);
> +				     ConnectionTypeBlocking, this, controls);
>  	if (ret)
>  		return ret;
>  
> diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
> index 4cedb32b..8a1918d5 100644
> --- a/src/libcamera/pipeline/ipu3/ipu3.cpp
> +++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
> @@ -105,7 +105,7 @@ public:
>  	int exportFrameBuffers(Camera *camera, Stream *stream,
>  			       std::vector<std::unique_ptr<FrameBuffer>> *buffers) override;
>  
> -	int start(Camera *camera) override;
> +	int start(Camera *camera, ControlList *controls) override;
>  	void stop(Camera *camera) override;
>  
>  	int queueRequestDevice(Camera *camera, Request *request) override;
> @@ -596,7 +596,7 @@ int PipelineHandlerIPU3::freeBuffers(Camera *camera)
>  	return 0;
>  }
>  
> -int PipelineHandlerIPU3::start(Camera *camera)
> +int PipelineHandlerIPU3::start(Camera *camera, [[maybe_unused]] ControlList *controls)

Could you wrap the line ?

int PipelineHandlerIPU3::start(Camera *camera,
			       [[maybe_unused]] ControlList *controls)

Same in a few places below.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

>  {
>  	IPU3CameraData *data = cameraData(camera);
>  	CIO2Device *cio2 = &data->cio2_;
> diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> index 6fcdf557..9937db73 100644
> --- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> +++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> @@ -242,7 +242,7 @@ public:
>  	int exportFrameBuffers(Camera *camera, Stream *stream,
>  			       std::vector<std::unique_ptr<FrameBuffer>> *buffers) override;
>  
> -	int start(Camera *camera) override;
> +	int start(Camera *camera, ControlList *controls) override;
>  	void stop(Camera *camera) override;
>  
>  	int queueRequestDevice(Camera *camera, Request *request) override;
> @@ -731,7 +731,7 @@ int PipelineHandlerRPi::exportFrameBuffers([[maybe_unused]] Camera *camera, Stre
>  	return ret;
>  }
>  
> -int PipelineHandlerRPi::start(Camera *camera)
> +int PipelineHandlerRPi::start(Camera *camera, [[maybe_unused]] ControlList *controls)
>  {
>  	RPiCameraData *data = cameraData(camera);
>  	int ret;
> diff --git a/src/libcamera/pipeline/rkisp1/rkisp1.cpp b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> index 6e74a49a..4e959fde 100644
> --- a/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> +++ b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> @@ -187,7 +187,7 @@ public:
>  	int exportFrameBuffers(Camera *camera, Stream *stream,
>  			       std::vector<std::unique_ptr<FrameBuffer>> *buffers) override;
>  
> -	int start(Camera *camera) override;
> +	int start(Camera *camera, ControlList *controls) override;
>  	void stop(Camera *camera) override;
>  
>  	int queueRequestDevice(Camera *camera, Request *request) override;
> @@ -832,7 +832,7 @@ int PipelineHandlerRkISP1::freeBuffers(Camera *camera)
>  	return 0;
>  }
>  
> -int PipelineHandlerRkISP1::start(Camera *camera)
> +int PipelineHandlerRkISP1::start(Camera *camera, [[maybe_unused]] ControlList *controls)
>  {
>  	RkISP1CameraData *data = cameraData(camera);
>  	int ret;
> diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
> index 0d3078f7..b047aeb9 100644
> --- a/src/libcamera/pipeline/simple/simple.cpp
> +++ b/src/libcamera/pipeline/simple/simple.cpp
> @@ -126,7 +126,7 @@ public:
>  	int exportFrameBuffers(Camera *camera, Stream *stream,
>  			       std::vector<std::unique_ptr<FrameBuffer>> *buffers) override;
>  
> -	int start(Camera *camera) override;
> +	int start(Camera *camera, ControlList *controls) override;
>  	void stop(Camera *camera) override;
>  
>  	bool match(DeviceEnumerator *enumerator) override;
> @@ -646,7 +646,7 @@ int SimplePipelineHandler::exportFrameBuffers(Camera *camera, Stream *stream,
>  		return data->video_->exportBuffers(count, buffers);
>  }
>  
> -int SimplePipelineHandler::start(Camera *camera)
> +int SimplePipelineHandler::start(Camera *camera, [[maybe_unused]] ControlList *controls)
>  {
>  	SimpleCameraData *data = cameraData(camera);
>  	V4L2VideoDevice *video = data->video_;
> diff --git a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
> index 0f3241cc..87b0f03d 100644
> --- a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
> +++ b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
> @@ -76,7 +76,7 @@ public:
>  	int exportFrameBuffers(Camera *camera, Stream *stream,
>  			       std::vector<std::unique_ptr<FrameBuffer>> *buffers) override;
>  
> -	int start(Camera *camera) override;
> +	int start(Camera *camera, ControlList *controls) override;
>  	void stop(Camera *camera) override;
>  
>  	int queueRequestDevice(Camera *camera, Request *request) override;
> @@ -236,7 +236,7 @@ int PipelineHandlerUVC::exportFrameBuffers(Camera *camera, Stream *stream,
>  	return data->video_->exportBuffers(count, buffers);
>  }
>  
> -int PipelineHandlerUVC::start(Camera *camera)
> +int PipelineHandlerUVC::start(Camera *camera, [[maybe_unused]] ControlList *controls)
>  {
>  	UVCCameraData *data = cameraData(camera);
>  	unsigned int count = data->stream_.configuration().bufferCount;
> diff --git a/src/libcamera/pipeline/vimc/vimc.cpp b/src/libcamera/pipeline/vimc/vimc.cpp
> index 914b6b54..d81b8598 100644
> --- a/src/libcamera/pipeline/vimc/vimc.cpp
> +++ b/src/libcamera/pipeline/vimc/vimc.cpp
> @@ -92,7 +92,7 @@ public:
>  	int exportFrameBuffers(Camera *camera, Stream *stream,
>  			       std::vector<std::unique_ptr<FrameBuffer>> *buffers) override;
>  
> -	int start(Camera *camera) override;
> +	int start(Camera *camera, ControlList *controls) override;
>  	void stop(Camera *camera) override;
>  
>  	int queueRequestDevice(Camera *camera, Request *request) override;
> @@ -313,7 +313,7 @@ int PipelineHandlerVimc::exportFrameBuffers(Camera *camera, Stream *stream,
>  	return data->video_->exportBuffers(count, buffers);
>  }
>  
> -int PipelineHandlerVimc::start(Camera *camera)
> +int PipelineHandlerVimc::start(Camera *camera, [[maybe_unused]] ControlList *controls)
>  {
>  	VimcCameraData *data = cameraData(camera);
>  	unsigned int count = data->stream_.configuration().bufferCount;
> diff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp
> index 894200ee..c75ebbd5 100644
> --- a/src/libcamera/pipeline_handler.cpp
> +++ b/src/libcamera/pipeline_handler.cpp
> @@ -351,6 +351,7 @@ const ControlList &PipelineHandler::properties(const Camera *camera) const
>   * \fn PipelineHandler::start()
>   * \brief Start capturing from a group of streams
>   * \param[in] camera The camera to start
> + * \param[in] controls Controls to be applied before starting the Camera
>   *
>   * Start the group of streams that have been configured for capture by
>   * \a configure(). The intended caller of this method is the Camera class which

Patch
diff mbox series 

diff --git a/Documentation/guides/pipeline-handler.rst b/Documentation/guides/pipeline-handler.rst
index 57aee455..63275a12 100644
--- a/Documentation/guides/pipeline-handler.rst
+++ b/Documentation/guides/pipeline-handler.rst
@@ -209,7 +209,7 @@  methods for the overridden class members.
           int exportFrameBuffers(Camera *camera, Stream *stream,
           std::vector<std::unique_ptr<FrameBuffer>> *buffers) override;
 
-          int start(Camera *camera) override;
+          int start(Camera *camera, ControlList *controls) override;
           void stop(Camera *camera) override;
 
           int queueRequestDevice(Camera *camera, Request *request) override;
@@ -239,7 +239,7 @@  methods for the overridden class members.
           return -1;
    }
 
-   int PipelineHandlerVivid::start(Camera *camera)
+   int PipelineHandlerVivid::start(Camera *camera, ControlList *controls)
    {
           return -1;
    }
diff --git a/include/libcamera/camera.h b/include/libcamera/camera.h
index 5c5f1a05..f94f8599 100644
--- a/include/libcamera/camera.h
+++ b/include/libcamera/camera.h
@@ -103,7 +103,7 @@  public:
 	std::unique_ptr<Request> createRequest(uint64_t cookie = 0);
 	int queueRequest(Request *request);
 
-	int start();
+	int start(ControlList *controls = nullptr);
 	int stop();
 
 private:
diff --git a/include/libcamera/internal/pipeline_handler.h b/include/libcamera/internal/pipeline_handler.h
index c12c8904..bd3c4a81 100644
--- a/include/libcamera/internal/pipeline_handler.h
+++ b/include/libcamera/internal/pipeline_handler.h
@@ -78,7 +78,7 @@  public:
 	virtual int exportFrameBuffers(Camera *camera, Stream *stream,
 				       std::vector<std::unique_ptr<FrameBuffer>> *buffers) = 0;
 
-	virtual int start(Camera *camera) = 0;
+	virtual int start(Camera *camera, ControlList *controls) = 0;
 	virtual void stop(Camera *camera) = 0;
 
 	int queueRequest(Camera *camera, Request *request);
diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
index bcb7b046..ffb63fb2 100644
--- a/src/libcamera/camera.cpp
+++ b/src/libcamera/camera.cpp
@@ -1003,9 +1003,10 @@  int Camera::queueRequest(Request *request)
 /**
  * \brief Start capture from camera
  *
- * Start the camera capture session. Once the camera is started the application
- * can queue requests to the camera to process and return to the application
- * until the capture session is terminated with \a stop().
+ * Start the camera capture session, optionally providing a list of controls to
+ * action before starting. Once the camera is started the application can queue
+ * requests to the camera to process and return to the application until the
+ * capture session is terminated with \a stop().
  *
  * \context This function may only be called when the camera is in the
  * Configured state as defined in \ref camera_operation, and shall be
@@ -1016,7 +1017,7 @@  int Camera::queueRequest(Request *request)
  * \retval -ENODEV The camera has been disconnected from the system
  * \retval -EACCES The camera is not in a state where it can be started
  */
-int Camera::start()
+int Camera::start(ControlList *controls)
 {
 	Private *const d = LIBCAMERA_D_PTR();
 
@@ -1027,7 +1028,7 @@  int Camera::start()
 	LOG(Camera, Debug) << "Starting capture";
 
 	ret = d->pipe_->invokeMethod(&PipelineHandler::start,
-				     ConnectionTypeBlocking, this);
+				     ConnectionTypeBlocking, this, controls);
 	if (ret)
 		return ret;
 
diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
index 4cedb32b..8a1918d5 100644
--- a/src/libcamera/pipeline/ipu3/ipu3.cpp
+++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
@@ -105,7 +105,7 @@  public:
 	int exportFrameBuffers(Camera *camera, Stream *stream,
 			       std::vector<std::unique_ptr<FrameBuffer>> *buffers) override;
 
-	int start(Camera *camera) override;
+	int start(Camera *camera, ControlList *controls) override;
 	void stop(Camera *camera) override;
 
 	int queueRequestDevice(Camera *camera, Request *request) override;
@@ -596,7 +596,7 @@  int PipelineHandlerIPU3::freeBuffers(Camera *camera)
 	return 0;
 }
 
-int PipelineHandlerIPU3::start(Camera *camera)
+int PipelineHandlerIPU3::start(Camera *camera, [[maybe_unused]] ControlList *controls)
 {
 	IPU3CameraData *data = cameraData(camera);
 	CIO2Device *cio2 = &data->cio2_;
diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
index 6fcdf557..9937db73 100644
--- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
+++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
@@ -242,7 +242,7 @@  public:
 	int exportFrameBuffers(Camera *camera, Stream *stream,
 			       std::vector<std::unique_ptr<FrameBuffer>> *buffers) override;
 
-	int start(Camera *camera) override;
+	int start(Camera *camera, ControlList *controls) override;
 	void stop(Camera *camera) override;
 
 	int queueRequestDevice(Camera *camera, Request *request) override;
@@ -731,7 +731,7 @@  int PipelineHandlerRPi::exportFrameBuffers([[maybe_unused]] Camera *camera, Stre
 	return ret;
 }
 
-int PipelineHandlerRPi::start(Camera *camera)
+int PipelineHandlerRPi::start(Camera *camera, [[maybe_unused]] ControlList *controls)
 {
 	RPiCameraData *data = cameraData(camera);
 	int ret;
diff --git a/src/libcamera/pipeline/rkisp1/rkisp1.cpp b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
index 6e74a49a..4e959fde 100644
--- a/src/libcamera/pipeline/rkisp1/rkisp1.cpp
+++ b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
@@ -187,7 +187,7 @@  public:
 	int exportFrameBuffers(Camera *camera, Stream *stream,
 			       std::vector<std::unique_ptr<FrameBuffer>> *buffers) override;
 
-	int start(Camera *camera) override;
+	int start(Camera *camera, ControlList *controls) override;
 	void stop(Camera *camera) override;
 
 	int queueRequestDevice(Camera *camera, Request *request) override;
@@ -832,7 +832,7 @@  int PipelineHandlerRkISP1::freeBuffers(Camera *camera)
 	return 0;
 }
 
-int PipelineHandlerRkISP1::start(Camera *camera)
+int PipelineHandlerRkISP1::start(Camera *camera, [[maybe_unused]] ControlList *controls)
 {
 	RkISP1CameraData *data = cameraData(camera);
 	int ret;
diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
index 0d3078f7..b047aeb9 100644
--- a/src/libcamera/pipeline/simple/simple.cpp
+++ b/src/libcamera/pipeline/simple/simple.cpp
@@ -126,7 +126,7 @@  public:
 	int exportFrameBuffers(Camera *camera, Stream *stream,
 			       std::vector<std::unique_ptr<FrameBuffer>> *buffers) override;
 
-	int start(Camera *camera) override;
+	int start(Camera *camera, ControlList *controls) override;
 	void stop(Camera *camera) override;
 
 	bool match(DeviceEnumerator *enumerator) override;
@@ -646,7 +646,7 @@  int SimplePipelineHandler::exportFrameBuffers(Camera *camera, Stream *stream,
 		return data->video_->exportBuffers(count, buffers);
 }
 
-int SimplePipelineHandler::start(Camera *camera)
+int SimplePipelineHandler::start(Camera *camera, [[maybe_unused]] ControlList *controls)
 {
 	SimpleCameraData *data = cameraData(camera);
 	V4L2VideoDevice *video = data->video_;
diff --git a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
index 0f3241cc..87b0f03d 100644
--- a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
+++ b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
@@ -76,7 +76,7 @@  public:
 	int exportFrameBuffers(Camera *camera, Stream *stream,
 			       std::vector<std::unique_ptr<FrameBuffer>> *buffers) override;
 
-	int start(Camera *camera) override;
+	int start(Camera *camera, ControlList *controls) override;
 	void stop(Camera *camera) override;
 
 	int queueRequestDevice(Camera *camera, Request *request) override;
@@ -236,7 +236,7 @@  int PipelineHandlerUVC::exportFrameBuffers(Camera *camera, Stream *stream,
 	return data->video_->exportBuffers(count, buffers);
 }
 
-int PipelineHandlerUVC::start(Camera *camera)
+int PipelineHandlerUVC::start(Camera *camera, [[maybe_unused]] ControlList *controls)
 {
 	UVCCameraData *data = cameraData(camera);
 	unsigned int count = data->stream_.configuration().bufferCount;
diff --git a/src/libcamera/pipeline/vimc/vimc.cpp b/src/libcamera/pipeline/vimc/vimc.cpp
index 914b6b54..d81b8598 100644
--- a/src/libcamera/pipeline/vimc/vimc.cpp
+++ b/src/libcamera/pipeline/vimc/vimc.cpp
@@ -92,7 +92,7 @@  public:
 	int exportFrameBuffers(Camera *camera, Stream *stream,
 			       std::vector<std::unique_ptr<FrameBuffer>> *buffers) override;
 
-	int start(Camera *camera) override;
+	int start(Camera *camera, ControlList *controls) override;
 	void stop(Camera *camera) override;
 
 	int queueRequestDevice(Camera *camera, Request *request) override;
@@ -313,7 +313,7 @@  int PipelineHandlerVimc::exportFrameBuffers(Camera *camera, Stream *stream,
 	return data->video_->exportBuffers(count, buffers);
 }
 
-int PipelineHandlerVimc::start(Camera *camera)
+int PipelineHandlerVimc::start(Camera *camera, [[maybe_unused]] ControlList *controls)
 {
 	VimcCameraData *data = cameraData(camera);
 	unsigned int count = data->stream_.configuration().bufferCount;
diff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp
index 894200ee..c75ebbd5 100644
--- a/src/libcamera/pipeline_handler.cpp
+++ b/src/libcamera/pipeline_handler.cpp
@@ -351,6 +351,7 @@  const ControlList &PipelineHandler::properties(const Camera *camera) const
  * \fn PipelineHandler::start()
  * \brief Start capturing from a group of streams
  * \param[in] camera The camera to start
+ * \param[in] controls Controls to be applied before starting the Camera
  *
  * Start the group of streams that have been configured for capture by
  * \a configure(). The intended caller of this method is the Camera class which