[libcamera-devel] [PATCH 1/3] include: linux: Add V4L2_CID_NOTIFY_GAINS control

[Laurent Pinchart]

Hi David,

On Thu, Dec 30, 2021 at 06:13:11PM +0200, Laurent Pinchart wrote:
> On Thu, Dec 30, 2021 at 10:52:54AM +0000, David Plowman wrote:
> > Hi Laurent
> > 
> > Sure, I can do that. Could you perhaps give me a few more hints, I
> > didn't really understand how looking at commits in include/linux was
> > helping me. Anyway, here's what I've done:
> > 
> > 1. I've cloned the whole of linuxtv-master onto my Pi.

By the way, we prefer updating to known tags from Linus' tree when
possible. As the V4L2_CID_NOTIFY_GAINS control has been merged in
v5.16-rc1, could you update to v5.16-rc7 instead of linuxtv/master ?

> > 2. I've run "utils/update-kernel-headers.sh <path-to-my-linuxtv-master>
> > 3. There were some warnings about intel-ipu3.h being missing, I assume
> > I can ignore that.
> > 4. Now I have about 7 files in include/linux that show up as
> > "modified", and one (intel-ipu3.h) is "deleted".
> 
> The path to intel-ipu3.h has changed in v5.14. I've just sent a patch to
> update the update-kernel-headers.sh script accordingly, and have CC'ed
> you.
> 
> > I'm guessing I shouldn't try and commit them all, so should I commit
> > just the one file that I care about (v4l2-controls.h)? But I can't
> > commit the whole v4l2-controls.h either, not least because it doesn't
> > compile (V4L2_CID_USER_BCM2835_ISP_BASE has disappeared), and it has
> > lots of other changes too. So maybe I just pick the single line that I
> > want? (only now it doesn't seem any different to what I did). So I've
> > rather managed to confuse myself!
> 
> Committing everything will indeed not work, as we carry local
> modifications for a few uAPI extensions that are not upstream yet. This
> includes
> 
> - In include/linux/drm_fourcc.h, the MJPEG and Bayer formats, the
>   DRM_FORMAT_MOD_VENDOR_MIPI modifier vendor prefix, the
>   IPU3_FORMAT_MOD_PACKED modifier and the MIPI_FORMAT_MOD_CSI2_PACKED
>   modifier.
> 
> - In include/linux/v4l2-controls.h, V4L2_CID_USER_BCM2835_ISP_BASE.
> 
> - In include/linux/videodev2.h, V4L2_META_FMT_SENSOR_DATA and
>   V4L2_META_FMT_BCM2835_ISP_STATS.
> 
> Those should be kept. All other modifications should be committed.
> 
> By the way, we could simplify the kernel headers update process by
> moving the definitions of V4L2_CID_USER_BCM2835_ISP_BASE,
> V4L2_META_FMT_SENSOR_DATA and V4L2_META_FMT_BCM2835_ISP_STATS to the
> Raspberry Pi pipeline handler and/or IPA as appropriate, until those get
> merged upstream.
> 
> > Thanks for your help!
> > 
> > On Fri, 24 Dec 2021 at 03:18, Laurent Pinchart wrote:
> > >
> > > Hi David,
> > >
> > > Thank you for the patch.
> > >
> > > On Thu, Dec 23, 2021 at 08:01:08AM +0000, David Plowman wrote:
> > > > Add this control which is already present upstream.
> > >
> > > We have a process to update the kernel headers. If possible, please use
> > > utils/update-kernel-headers.sh. You will need to then pick changes
> > > manually to avoid dropping the currently not upstream features. The git
> > > log for the include/linux/ directory can show you examples.
> > >
> > > > Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
> > > > ---
> > > >  include/linux/v4l2-controls.h | 1 +
> > > >  1 file changed, 1 insertion(+)
> > > >
> > > > diff --git a/include/linux/v4l2-controls.h b/include/linux/v4l2-controls.h
> > > > index 59a57418..9db06cb2 100644
> > > > --- a/include/linux/v4l2-controls.h
> > > > +++ b/include/linux/v4l2-controls.h
> > > > @@ -1109,6 +1109,7 @@ enum v4l2_jpeg_chroma_subsampling {
> > > >  #define V4L2_CID_TEST_PATTERN_BLUE           (V4L2_CID_IMAGE_SOURCE_CLASS_BASE + 6)
> > > >  #define V4L2_CID_TEST_PATTERN_GREENB         (V4L2_CID_IMAGE_SOURCE_CLASS_BASE + 7)
> > > >  #define V4L2_CID_UNIT_CELL_SIZE                      (V4L2_CID_IMAGE_SOURCE_CLASS_BASE + 8)
> > > > +#define V4L2_CID_NOTIFY_GAINS                        (V4L2_CID_IMAGE_SOURCE_CLASS_BASE + 9)
> > > >
> > > >
> > > >  /* Image processing controls */

-- 
Regards,

Laurent Pinchart