| Message ID | 20171208140128.19740-1-p.zabel@pengutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Philipp, On Fri, Dec 08, 2017 at 03:01:28PM +0100, Philipp Zabel wrote: > V4L2_BUF_FLAG_LAST is a signal from the driver to userspace for buffers > on the capture queue. When userspace queues back a capture buffer with > the flag set, we should clear it. > > Otherwise, if userspace restarts streaming after EOS, without > reallocating the buffers, mem2mem devices will erroneously signal EOS > prematurely, as soon as the already flagged buffer is dequeued. > > Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de> > --- > drivers/media/v4l2-core/videobuf2-v4l2.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/media/v4l2-core/videobuf2-v4l2.c b/drivers/media/v4l2-core/videobuf2-v4l2.c > index 4075314a69893..fac3cd6f901d5 100644 > --- a/drivers/media/v4l2-core/videobuf2-v4l2.c > +++ b/drivers/media/v4l2-core/videobuf2-v4l2.c > @@ -434,6 +434,8 @@ static int __fill_vb2_buffer(struct vb2_buffer *vb, > } else { > /* Zero any output buffer flags as this is a capture buffer */ > vbuf->flags &= ~V4L2_BUFFER_OUT_FLAGS; > + /* Zero last flag, this is a signal from driver to userspace */ > + vbuf->flags &= ~V4L2_BUF_FLAG_LAST; Thanks for the patch. How about: vbuf->flags &= ~(V4L2_BUFFER_OUT_FLAGS | V4L2_BUF_FLAG_LAST);
diff --git a/drivers/media/v4l2-core/videobuf2-v4l2.c b/drivers/media/v4l2-core/videobuf2-v4l2.c index 4075314a69893..fac3cd6f901d5 100644 --- a/drivers/media/v4l2-core/videobuf2-v4l2.c +++ b/drivers/media/v4l2-core/videobuf2-v4l2.c @@ -434,6 +434,8 @@ static int __fill_vb2_buffer(struct vb2_buffer *vb, } else { /* Zero any output buffer flags as this is a capture buffer */ vbuf->flags &= ~V4L2_BUFFER_OUT_FLAGS; + /* Zero last flag, this is a signal from driver to userspace */ + vbuf->flags &= ~V4L2_BUF_FLAG_LAST; } return 0;
V4L2_BUF_FLAG_LAST is a signal from the driver to userspace for buffers on the capture queue. When userspace queues back a capture buffer with the flag set, we should clear it. Otherwise, if userspace restarts streaming after EOS, without reallocating the buffers, mem2mem devices will erroneously signal EOS prematurely, as soon as the already flagged buffer is dequeued. Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de> --- drivers/media/v4l2-core/videobuf2-v4l2.c | 2 ++ 1 file changed, 2 insertions(+)