[PATCH 1/1] libcamera: Extend V4L2 videodevice to accept media request API

[Harvey Yang]

From: Han-Lin Chen <hanlinchen at chromium.org>

Add request fd as an extra argument to V4L2 device queueBuffer.
Default to -1 for backward compatibility.

It's used to bind multiple buffers into the same request.

Signed-off-by: Han-Lin Chen <hanlinchen at chromium.org>
Co-developed-by: Harvey Yang <chenghaoyang at chromium.org>
Signed-off-by: Harvey Yang <chenghaoyang at chromium.org>
---
 include/libcamera/internal/v4l2_videodevice.h | 2 +-
 src/libcamera/v4l2_videodevice.cpp            | 7 ++++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/libcamera/internal/v4l2_videodevice.h b/include/libcamera/internal/v4l2_videodevice.h
index f021c2a01..6e2b1e1f1 100644
--- a/include/libcamera/internal/v4l2_videodevice.h
+++ b/include/libcamera/internal/v4l2_videodevice.h
@@ -218,7 +218,7 @@ public:
 	int importBuffers(unsigned int count);
 	int releaseBuffers();
 
-	int queueBuffer(FrameBuffer *buffer);
+	int queueBuffer(FrameBuffer *buffer, int requestFd = -1);
 	Signal<FrameBuffer *> bufferReady;
 
 	int streamOn();
diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
index 14eba0561..0c6ea086d 100644
--- a/src/libcamera/v4l2_videodevice.cpp
+++ b/src/libcamera/v4l2_videodevice.cpp
@@ -1604,6 +1604,7 @@ int V4L2VideoDevice::releaseBuffers()
 /**
  * \brief Queue a buffer to the video device
  * \param[in] buffer The buffer to be queued
+ * \param[in] requestFd The fd of the request to queue the buffer to
  *
  * For capture video devices the \a buffer will be filled with data by the
  * device. For output video devices the \a buffer shall contain valid data and
@@ -1618,7 +1619,7 @@ int V4L2VideoDevice::releaseBuffers()
  *
  * \return 0 on success or a negative error code otherwise
  */
-int V4L2VideoDevice::queueBuffer(FrameBuffer *buffer)
+int V4L2VideoDevice::queueBuffer(FrameBuffer *buffer, int requestFd)
 {
 	struct v4l2_plane v4l2Planes[VIDEO_MAX_PLANES] = {};
 	struct v4l2_buffer buf = {};
@@ -1647,6 +1648,10 @@ int V4L2VideoDevice::queueBuffer(FrameBuffer *buffer)
 	buf.type = bufferType_;
 	buf.memory = memoryType_;
 	buf.field = V4L2_FIELD_NONE;
+	if (requestFd >= 0) {
+		buf.flags |= V4L2_BUF_FLAG_REQUEST_FD;
+		buf.request_fd = requestFd;
+	}
 
 	bool multiPlanar = V4L2_TYPE_IS_MULTIPLANAR(buf.type);
 	const std::vector<FrameBuffer::Plane> &planes = buffer->planes();
-- 
2.47.0.277.g8800431eea-goog