Hi Dave, thanks for the comments On Tue, Jul 04, 2023 at 10:58:11AM +0100, Dave Stevenson wrote: > Hi Jacopo > > Thanks for adding documentation. > Sorry I couldn't be at your presentation, but I'll find the slides > (and recording if there is one). > videos and slides should be already available for attendees. If not I can send you the slide deck, but trust me, there is nothing new for you there. > On Mon, 3 Jul 2023 at 21:29, Jacopo Mondi <jacopo.mondi@xxxxxxxxxxxxxxxx> wrote: > > > > Document the requirement of notifying to userspace the possible > > re-ordering of the color sample components when a vertical or horizontal > > flip is applied to a RAW camera sensor. > > > > Signed-off-by: Jacopo Mondi <jacopo.mondi@xxxxxxxxxxxxxxxx> > > --- > > Documentation/driver-api/media/camera-sensor.rst | 16 ++++++++++++++++ > > 1 file changed, 16 insertions(+) > > > > diff --git a/Documentation/driver-api/media/camera-sensor.rst b/Documentation/driver-api/media/camera-sensor.rst > > index 93f4f2536c25..ee4a7fe5f72a 100644 > > --- a/Documentation/driver-api/media/camera-sensor.rst > > +++ b/Documentation/driver-api/media/camera-sensor.rst > > @@ -173,3 +173,19 @@ V4L2_CID_VFLIP controls with the values programmed by the register sequences. > > The default values of these controls shall be 0 (disabled). Especially these > > controls shall not be inverted, independently of the sensor's mounting > > rotation. > > + > > +Flip handling for raw camera sensors > > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > Possibly "for colour raw camera sensors". > Mono sensors are still raw in that they need processing for black > level, lens shading, etc, but they won't change the colour ordering. > Thanks, good point > > + > > +Applying vertical and horizontal flips on raw camera sensors inverts the color > > +sample reading direction on the sensor's pixel array. This causes the > > +re-ordering of the color samples on the sensor's output frame. > > This *may* cause the re-ordering.... > > Not all sensors do. Some shift the readout by one line/column to keep > the Bayer order the same, and technically should update the selection. > OnSemi sensors in particular seem to do this, as do the Sony > IMX327/290/462 family. > Is it the driver doing the shift or is it the sensor automatically adjusting ? > > As an example, a > > +raw camera sensor with a Bayer pattern color filter array and a native RGGB > > +Bayer order will produce frames with GRBG component ordering when a vertical > > +flip is applied. > > Vertical flip of RGGB would be GBRG as the RG and GB get swapped, not > GRBG (which would be horizontal flip). I clearly mean horizontal sorry. I'll fix. Thanks j > > Dave > > > Camera sensor drivers where inverting the reading order > > +direction causes a re-ordering of the color components are requested to register > > +the ``V4L2_CID_VFLIP`` and ``V4L2_CID_HFLIP`` controls with the > > +``V4L2_CTRL_FLAG_MODIFY_LAYOUT`` flag enabled to notify userspace that enabling > > +a flip can potentially change the output buffer content layout. Flips should > > +also be taken into account when enumerating and handling media bus formats > > +on the camera sensor source pads. > > -- > > 2.40.1 > >
