Patch "[media] v4l: vb2: Fix stream start and buffer completion race" has a
sets q->start_streaming_called before calling queue op start_streaming() in
order to fix a bug. This has the side effect that buffers returned to
videobuf2 in VB2_BUF_STATE_QUEUED will cause a WARN_ON() to be called.
Add a new field called done_buffers_queued_state to struct vb2_queue, which
must be set if the new state of buffers returned to videobuf2 must be
VB2_BUF_STATE_QUEUED, i.e. buffers returned in start_streaming op.
Signed-off-by: Sakari Ailus <sakari.ai...@iki.fi>
Cc: Hans Verkuil <hverk...@xs4all.nl>
---
drivers/media/v4l2-core/videobuf2-core.c | 5 +++--
include/media/videobuf2-core.h | 4 ++++
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/media/v4l2-core/videobuf2-core.c
b/drivers/media/v4l2-core/videobuf2-core.c
index 7e6aff6..202e2a5 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -1174,7 +1174,7 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum
vb2_buffer_state state)
if (WARN_ON(vb->state != VB2_BUF_STATE_ACTIVE))
return;
- if (!q->start_streaming_called) {
+ if (q->done_buffers_queued_state) {
if (WARN_ON(state != VB2_BUF_STATE_QUEUED))
state = VB2_BUF_STATE_QUEUED;
} else if (WARN_ON(state != VB2_BUF_STATE_DONE &&
@@ -1742,9 +1742,10 @@ static int vb2_start_streaming(struct vb2_queue *q)
__enqueue_in_driver(vb);
/* Tell the driver to start streaming */
- q->start_streaming_called = 1;
+ q->done_buffers_queued_state = q->start_streaming_called = 1;
ret = call_qop(q, start_streaming, q,
atomic_read(&q->owned_by_drv_count));
+ q->done_buffers_queued_state = 0;
if (!ret)
return 0;
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 5a10d8d..7c0dac6 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -380,6 +380,9 @@ struct v4l2_fh;
* @streaming: current streaming state
* @start_streaming_called: start_streaming() was called successfully and we
* started streaming.
+ * @done_buffers_queued_state: buffers returned to videobuf2 must go
+ * to VB2_BUF_STATE_QUEUED state. This is the case whilst
+ * the driver's start_streaming op is called.
* @error: a fatal error occurred on the queue
* @fileio: file io emulator internal data, used only if emulator is active
* @threadio: thread io internal data, used only if thread is active
@@ -418,6 +421,7 @@ struct vb2_queue {
unsigned int streaming:1;
unsigned int start_streaming_called:1;
+ unsigned int done_buffers_queued_state:1;
unsigned int error:1;
struct vb2_fileio_data *fileio;
--
1.7.10.4
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