[PATCH for v3.17] 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.verk...@cisco.com
---
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
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Re: [PATCH for v3.17] videobuf2-core: add comments before the WARN_ON
On Mon, Aug 4, 2014 at 2:36 PM, Hans Verkuil hverk...@xs4all.nl wrote:
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.verk...@cisco.com
Acked-by: Pawel Osciak pa...@osciak.com
---
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
--
Best regards,
Pawel Osciak
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