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| author | Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> | 2014-06-23 18:00:22 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <m.chehab@samsung.com> | 2014-07-17 12:44:48 -0300 |
| commit | bd994ddb2a12a3ff48cd549ec82cdceaea9614df (patch) | |
| tree | 82729e4916109356556974e0703108fa1c3cdd7c | |
| parent | c96fd46afb34a554406bce9784126b96ad09091e (diff) | |
| download | op-kernel-dev-bd994ddb2a12a3ff48cd549ec82cdceaea9614df.zip op-kernel-dev-bd994ddb2a12a3ff48cd549ec82cdceaea9614df.tar.gz | |
[media] v4l: vb2: Fix stream start and buffer completion race
videobuf2 stores the driver streaming state internally in the queue in
the start_streaming_called variable. The state is set right after the
driver start_stream operation returns, and checked in the
vb2_buffer_done() function, typically called from the frame completion
interrupt handler. A race condition exists if the hardware finishes
processing the first frame before the start_stream operation returns.
Fix this by setting start_streaming_called to 1 before calling the
start_stream operation, and resetting it to 0 if the operation fails.
Cc: stable@vger.kernel.org # for v3.15 and up
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
| -rw-r--r-- | drivers/media/v4l2-core/videobuf2-core.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c index 7c4489c..1d67e95 100644 --- a/drivers/media/v4l2-core/videobuf2-core.c +++ b/drivers/media/v4l2-core/videobuf2-core.c @@ -1750,12 +1750,14 @@ static int vb2_start_streaming(struct vb2_queue *q) __enqueue_in_driver(vb); /* Tell the driver to start streaming */ + q->start_streaming_called = 1; ret = call_qop(q, start_streaming, q, atomic_read(&q->owned_by_drv_count)); - q->start_streaming_called = ret == 0; if (!ret) return 0; + q->start_streaming_called = 0; + dprintk(1, "driver refused to start streaming\n"); if (WARN_ON(atomic_read(&q->owned_by_drv_count))) { unsigned i; |
