[libcamera-devel] [PATCH v4 21/22] v4l2: v4l2_camera_proxy: Fix buffer flags related to queueing

[Paul Elder]

Fix buffer flags related to queueing and dequeueing:
- don't allow a buffer with the same index that is already in the queue
  to be enqueued again
- don't clear the done flag upon qbuf
- do clear the done flag upon dqbuf
- set the flags in V4L2CameraProxy's internal buffers, and not just in
  the buffers returned from qbuf

Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

---
Changes in v4:
- fix the V4L2_BUF_FLAG_DONE flag properly
  - clear in dqbuf, set in updateBuffers (latter is already there)

Changes in v3:
- remove "set the mapped flag on enqueueing"
- clean up some logic
- expand commit message very slightly

New in v2
- split from "Fix v4l2-compliance streaming tests"
---
 src/v4l2/v4l2_camera_proxy.cpp | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp
index d5c146f..3b7a6f4 100644
--- a/src/v4l2/v4l2_camera_proxy.cpp
+++ b/src/v4l2/v4l2_camera_proxy.cpp
@@ -567,6 +567,9 @@ int V4L2CameraProxy::vidioc_qbuf(V4L2CameraFile *file, struct v4l2_buffer *arg)
 	if (arg->index >= bufferCount_)
 		return -EINVAL;
 
+	if (buffers_[arg->index].flags & V4L2_BUF_FLAG_QUEUED)
+		return -EINVAL;
+
 	if (!hasOwnership(file))
 		return -EBUSY;
 
@@ -579,8 +582,9 @@ int V4L2CameraProxy::vidioc_qbuf(V4L2CameraFile *file, struct v4l2_buffer *arg)
 	if (ret < 0)
 		return ret;
 
-	arg->flags |= V4L2_BUF_FLAG_QUEUED;
-	arg->flags &= ~V4L2_BUF_FLAG_DONE;
+	buffers_[arg->index].flags |= V4L2_BUF_FLAG_QUEUED;
+
+	arg->flags = buffers_[arg->index].flags;
 
 	return ret;
 }
@@ -618,7 +622,7 @@ int V4L2CameraProxy::vidioc_dqbuf(V4L2CameraFile *file, struct v4l2_buffer *arg)
 
 	struct v4l2_buffer &buf = buffers_[currentBuf_];
 
-	buf.flags &= ~V4L2_BUF_FLAG_QUEUED;
+	buf.flags &= ~(V4L2_BUF_FLAG_QUEUED | V4L2_BUF_FLAG_DONE);
 	buf.length = sizeimage_;
 	*arg = buf;
 
-- 
2.27.0