libcamera: v4l2_device: Support queueing buffers to an output device

To queue a buffer to an output device, we must set the buffer properties.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

1 files changed, 16 insertions, 1 deletions

diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
index e9709906..77866efb 100644
--- a/src/libcamera/v4l2_device.cpp
+++ b/src/libcamera/v4l2_device.cpp
@@ -299,7 +299,15 @@ int V4L2Device::open()
 			    ? V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE
 			    : V4L2_BUF_TYPE_VIDEO_OUTPUT;
 
-	fdEvent_ = new EventNotifier(fd_, EventNotifier::Read);
+	/*
+	 *  We wait for Read notifications on CAPTURE devices (POLLIN), and
+	 *  Write notifications for OUTPUT devices (POLLOUT).
+	 */
+	if (caps_.isCapture())
+		fdEvent_ = new EventNotifier(fd_, EventNotifier::Read);
+	else
+		fdEvent_ = new EventNotifier(fd_, EventNotifier::Write);
+
 	fdEvent_->activated.connect(this, &V4L2Device::bufferAvailable);
 	fdEvent_->setEnabled(false);
 
@@ -677,6 +685,13 @@ int V4L2Device::queueBuffer(Buffer *buffer)
 		buf.m.planes = planes;
 	}
 
+	if (V4L2_TYPE_IS_OUTPUT(bufferType_)) {
+		buf.bytesused = buffer->bytesused_;
+		buf.sequence = buffer->sequence_;
+		buf.timestamp.tv_sec = buffer->timestamp_ / 1000000000;
+		buf.timestamp.tv_usec = (buffer->timestamp_ / 1000) % 1000000;
+	}
+
 	LOG(V4L2, Debug) << "Queueing buffer " << buf.index;
 
 	ret = ioctl(fd_, VIDIOC_QBUF, &buf);