Recently WARN_ON() calls have been added to warn if the driver is not properly returning buffers to vb2 in start_streaming (if it fails) or stop_streaming(). Add comments before those WARN_ON calls that refer to the videobuf2-core.h header that explains what drivers are supposed to do in these situations. That should help point developers in the right direction if they see these warnings.
Signed-off-by: Hans Verkuil <[email protected]> --- drivers/media/v4l2-core/videobuf2-core.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c index c359006..d3f2a22 100644 --- a/drivers/media/v4l2-core/videobuf2-core.c +++ b/drivers/media/v4l2-core/videobuf2-core.c @@ -1762,6 +1762,12 @@ static int vb2_start_streaming(struct vb2_queue *q) q->start_streaming_called = 0; dprintk(1, "driver refused to start streaming\n"); + /* + * If you see this warning, then the driver isn't cleaning up properly + * after a failed start_streaming(). See the start_streaming() + * documentation in videobuf2-core.h for more information how buffers + * should be returned to vb2 in start_streaming(). + */ if (WARN_ON(atomic_read(&q->owned_by_drv_count))) { unsigned i; @@ -2123,6 +2129,12 @@ static void __vb2_queue_cancel(struct vb2_queue *q) if (q->start_streaming_called) call_void_qop(q, stop_streaming, q); + /* + * If you see this warning, then the driver isn't cleaning up properly + * in stop_streaming(). See the stop_streaming() documentation in + * videobuf2-core.h for more information how buffers should be returned + * to vb2 in stop_streaming(). + */ if (WARN_ON(atomic_read(&q->owned_by_drv_count))) { for (i = 0; i < q->num_buffers; ++i) if (q->bufs[i]->state == VB2_BUF_STATE_ACTIVE) -- 2.0.1 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
