[libcamera-devel,v5,5/8] libcamera: v4l2_videodevice: Better tracking of the device state
diff mbox series

Message ID 20220325090903.880311-6-naush@raspberrypi.com
State Accepted
Headers show
Series
  • Raspberry Pi: Efficient start/stop/start sequences
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Commit Message

Naushir Patuck March 25, 2022, 9:09 a.m. UTC 
Replace the existing streaming_ state variable with an enum to track the
following three state: Streaming, Stopping, and Stopped. The alternate states
will be used in a subsequent commit.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
---
 include/libcamera/internal/v4l2_videodevice.h |  3 ++-
 src/libcamera/v4l2_videodevice.cpp            | 10 ++++++----
 2 files changed, 8 insertions(+), 5 deletions(-)

Comments

Laurent Pinchart March 27, 2022, 11:10 p.m. UTC | #1 
Hi Naush,

Thank you for the patch.

On Fri, Mar 25, 2022 at 09:09:00AM +0000, Naushir Patuck via libcamera-devel wrote:
> Replace the existing streaming_ state variable with an enum to track the
> following three state: Streaming, Stopping, and Stopped. The alternate states
> will be used in a subsequent commit.
> 
> Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
> ---
>  include/libcamera/internal/v4l2_videodevice.h |  3 ++-
>  src/libcamera/v4l2_videodevice.cpp            | 10 ++++++----
>  2 files changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/include/libcamera/internal/v4l2_videodevice.h b/include/libcamera/internal/v4l2_videodevice.h
> index 2d2ccc477c91..32e022543385 100644
> --- a/include/libcamera/internal/v4l2_videodevice.h
> +++ b/include/libcamera/internal/v4l2_videodevice.h
> @@ -258,7 +258,8 @@ private:
>  
>  	EventNotifier *fdBufferNotifier_;
>  
> -	bool streaming_;
> +	enum class State { Streaming, Stopping, Stopped };

	enum class State {
		Streaming,
		Stopping,
		Stopped,
	};

and this should go right after LIBCAMERA_DISABLE_COPY() as we declare
types before functions and variables.

With this,

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

> +	State state_;
>  };
>  
>  class V4L2M2MDevice
> diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
> index 5f36ee20710d..9cea6a608660 100644
> --- a/src/libcamera/v4l2_videodevice.cpp
> +++ b/src/libcamera/v4l2_videodevice.cpp
> @@ -507,7 +507,7 @@ const std::string V4L2DeviceFormat::toString() const
>   */
>  V4L2VideoDevice::V4L2VideoDevice(const std::string &deviceNode)
>  	: V4L2Device(deviceNode), formatInfo_(nullptr), cache_(nullptr),
> -	  fdBufferNotifier_(nullptr), streaming_(false)
> +	  fdBufferNotifier_(nullptr), state_(State::Stopped)
>  {
>  	/*
>  	 * We default to an MMAP based CAPTURE video device, however this will
> @@ -1796,7 +1796,7 @@ int V4L2VideoDevice::streamOn()
>  		return ret;
>  	}
>  
> -	streaming_ = true;
> +	state_ = State::Streaming;
>  
>  	return 0;
>  }
> @@ -1818,7 +1818,7 @@ int V4L2VideoDevice::streamOff()
>  {
>  	int ret;
>  
> -	if (!streaming_ && queuedBuffers_.empty())
> +	if (state_ != State::Streaming && queuedBuffers_.empty())
>  		return 0;
>  
>  	ret = ioctl(VIDIOC_STREAMOFF, &bufferType_);
> @@ -1828,6 +1828,8 @@ int V4L2VideoDevice::streamOff()
>  		return ret;
>  	}
>  
> +	state_ = State::Stopping;
> +
>  	/* Send back all queued buffers. */
>  	for (auto it : queuedBuffers_) {
>  		FrameBuffer *buffer = it.second;
> @@ -1838,7 +1840,7 @@ int V4L2VideoDevice::streamOff()
>  
>  	queuedBuffers_.clear();
>  	fdBufferNotifier_->setEnabled(false);
> -	streaming_ = false;
> +	state_ = State::Stopped;
>  
>  	return 0;
>  }

Patch
diff mbox series 

diff --git a/include/libcamera/internal/v4l2_videodevice.h b/include/libcamera/internal/v4l2_videodevice.h
index 2d2ccc477c91..32e022543385 100644
--- a/include/libcamera/internal/v4l2_videodevice.h
+++ b/include/libcamera/internal/v4l2_videodevice.h
@@ -258,7 +258,8 @@  private:
 
 	EventNotifier *fdBufferNotifier_;
 
-	bool streaming_;
+	enum class State { Streaming, Stopping, Stopped };
+	State state_;
 };
 
 class V4L2M2MDevice
diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
index 5f36ee20710d..9cea6a608660 100644
--- a/src/libcamera/v4l2_videodevice.cpp
+++ b/src/libcamera/v4l2_videodevice.cpp
@@ -507,7 +507,7 @@  const std::string V4L2DeviceFormat::toString() const
  */
 V4L2VideoDevice::V4L2VideoDevice(const std::string &deviceNode)
 	: V4L2Device(deviceNode), formatInfo_(nullptr), cache_(nullptr),
-	  fdBufferNotifier_(nullptr), streaming_(false)
+	  fdBufferNotifier_(nullptr), state_(State::Stopped)
 {
 	/*
 	 * We default to an MMAP based CAPTURE video device, however this will
@@ -1796,7 +1796,7 @@  int V4L2VideoDevice::streamOn()
 		return ret;
 	}
 
-	streaming_ = true;
+	state_ = State::Streaming;
 
 	return 0;
 }
@@ -1818,7 +1818,7 @@  int V4L2VideoDevice::streamOff()
 {
 	int ret;
 
-	if (!streaming_ && queuedBuffers_.empty())
+	if (state_ != State::Streaming && queuedBuffers_.empty())
 		return 0;
 
 	ret = ioctl(VIDIOC_STREAMOFF, &bufferType_);
@@ -1828,6 +1828,8 @@  int V4L2VideoDevice::streamOff()
 		return ret;
 	}
 
+	state_ = State::Stopping;
+
 	/* Send back all queued buffers. */
 	for (auto it : queuedBuffers_) {
 		FrameBuffer *buffer = it.second;
@@ -1838,7 +1840,7 @@  int V4L2VideoDevice::streamOff()
 
 	queuedBuffers_.clear();
 	fdBufferNotifier_->setEnabled(false);
-	streaming_ = false;
+	state_ = State::Stopped;
 
 	return 0;
 }