| Message ID | 20211022100042.4187349-1-kieran.bingham@ideasonboard.com |
|---|---|
| State | Accepted |
| Commit | 1402152ad35017a817b1ead55e60ace9353efbdb |
| Headers | show |
| Series |
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| Related | show |
Hi Kieran, On Fri, Oct 22, 2021 at 11:00:42AM +0100, Kieran Bingham wrote: > The ternary operation used to get the total bytesused of a V4L2 single > planar format which is stored in a multiplanar buffer can easily be > mis-read to think it's a bug, and appears to be reading the value of the > first of N planes as the total. > > Directly explain the reasoning for why it looks like the condition is > inverted, as it is correct that the total bytes used is stored in only > the first plane of the multiplanar buffer. > > Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com> Reviewed-by: Paul Elder <paul.elder@ideasonboard.com> > > --- > v2: > - Update with more descriptive text from Laurent > > src/libcamera/v4l2_videodevice.cpp | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp > index 2745e5798419..0cc622f91f2d 100644 > --- a/src/libcamera/v4l2_videodevice.cpp > +++ b/src/libcamera/v4l2_videodevice.cpp > @@ -1711,6 +1711,13 @@ FrameBuffer *V4L2VideoDevice::dequeueBuffer() > return buffer; > } > > + /* > + * With a V4L2 single-planar format, all the data is stored in > + * a single memory plane. The number of bytes used is conveyed > + * through that plane when using the V4L2 multi-planar API, or > + * set directly in the buffer when using the V4L2 single-planar > + * API. > + */ > unsigned int bytesused = multiPlanar ? planes[0].bytesused > : buf.bytesused; > unsigned int remaining = bytesused; > -- > 2.30.2 >
diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp index 2745e5798419..0cc622f91f2d 100644 --- a/src/libcamera/v4l2_videodevice.cpp +++ b/src/libcamera/v4l2_videodevice.cpp @@ -1711,6 +1711,13 @@ FrameBuffer *V4L2VideoDevice::dequeueBuffer() return buffer; } + /* + * With a V4L2 single-planar format, all the data is stored in + * a single memory plane. The number of bytes used is conveyed + * through that plane when using the V4L2 multi-planar API, or + * set directly in the buffer when using the V4L2 single-planar + * API. + */ unsigned int bytesused = multiPlanar ? planes[0].bytesused : buf.bytesused; unsigned int remaining = bytesused;