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| author | Hans Verkuil <hans.verkuil@cisco.com> | 2014-08-04 07:33:53 +0200 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@osg.samsung.com> | 2014-09-22 01:45:03 +0200 |
| commit | 23cd08c8f72405359862aff2ad2a8be1c232198c (patch) | |
| tree | b507112fcc5548e723690be4aff1e3772c7c6df9 | |
| parent | [media] videobuf2-dma-sg: fix for wrong GFP mask to sg_alloc_table_from_pages (diff) | |
| download | linux-23cd08c8f72405359862aff2ad2a8be1c232198c.tar.xz linux-23cd08c8f72405359862aff2ad2a8be1c232198c.zip | |
[media] videobuf2-core: add comments before the WARN_ON
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 <hans.verkuil@cisco.com>
Acked-by: Pawel Osciak <pawel@osciak.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
| -rw-r--r-- | drivers/media/v4l2-core/videobuf2-core.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c index c359006074a8..d3f2a221db62 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) |