[libcamera-devel] [PATCH 00/11] Support OV7251 in IPU3 pipeline and qcam

[Laurent Pinchart]

On Mon, Mar 20, 2023 at 08:56:00AM +0100, Jacopo Mondi via libcamera-devel wrote:
> Hi Dan
> 
> On Sat, Mar 18, 2023 at 11:40:03PM +0000, Daniel Scally via libcamera-devel wrote:
> > Hello all
> >
> > This series is an attempt at adding support for the OV7251 camera on Microsoft
> > Surface platforms to libcamera. The sensor outputs data in MEDIA_BUS_FMT_Y10_1X10
> > format, which is packed by the CIO2 CSI-2 reciever into V4L2_PIX_FMT_IPU3_Y10. As
> > far as I know, these data are not intended to run through the Imgu at all. Certainly
> 
> Aren't they ? How can an application generically display Y10 if it
> receives data packed in a platform-specific format ?

This will require platform-specific applications :-(

> > the kernel's ipu3-imgu driver does not support that format, but given the simplicity
> 
> Maybe it is still just missing from the driver ? Should we ask the
> maintainers of the driver if it is just missing or it is not supported
> at all ? From a quick glance I have't find a trivial way to add Y10
> support to imgu_css_formats[]

It's most likely possible at the hardware level, but the information we
have is that at least the firmware doesn't support skipping the CFA
interpolation.

> > of the format we can simply use the CIO2 device's capture-capable devnode as the
> > source of the image data.
> >
> > To facilitate that, I'm identifying sensors which don't have a format that needs
> > the Imgu and simply skipping the Imgu/IPA processing in the IPU3 pipeline for
> > them.
> >
> > What I don't particularly like about the way that I've done things here is that
> > the stream only works for the Raw role, which feels wrong. The advantage is that
> > it's contained within the existing IPU3 pipeline without too much disruption,
> > but I do wonder whether a separate CIO2-only pipeline might not be better. In
> > that case PipelineHandlerIPU3::match() would need amending to check whether the
> > sensor for each "ipu3-csi-2 n" instance needed hooking into the Imgu and not adding
> > those to the device match if it found that they didn't need it, so that a new
> > CIO2-only pipeline could claim the media devices. I'd love to hear other people's
> > thoughts about the best way to handle this.
> >
> > Thanks
> > Dan
> >
> > Daniel Scally (11):
> >   pipeline: ipu3: Check if sensor supports test pattern control
> >   include: drm_fourcc: Add Y10 format
> >   libcamera/formats: Add IPU3_Y10 format
> >   pipeline: ipu3: Identify sensors that do not need the Imgu
> >   pipeline: ipu3: Add needsImgu flag to IPU3Frames
> >   pipeline: ipu3: Support sensors using only CIO2
> >   pipeline: ipu3: Allow raw-only streams in IPU3 pipeline
> >   pipeline: ipu3: Support IPU3_Y10 format
> >   apps: qcam: Add support for IPU3_Y10
> >   apps: qcam: Remove restriction on raw-only streams
> >   pipeline: ipu3: Increase maximum connected cameras
> >
> >  include/linux/drm_fourcc.h             |   3 +
> >  src/apps/qcam/format_converter.cpp     |  50 +++++
> >  src/apps/qcam/format_converter.h       |   2 +
> >  src/apps/qcam/main_window.cpp          |   6 -
> >  src/libcamera/formats.cpp              |  10 +
> >  src/libcamera/formats.yaml             |   3 +
> >  src/libcamera/pipeline/ipu3/cio2.cpp   |  21 +++
> >  src/libcamera/pipeline/ipu3/cio2.h     |   4 +
> >  src/libcamera/pipeline/ipu3/frames.cpp |  45 +++--
> >  src/libcamera/pipeline/ipu3/frames.h   |   3 +-
> >  src/libcamera/pipeline/ipu3/ipu3.cpp   | 242 ++++++++++++++-----------
> >  11 files changed, 255 insertions(+), 134 deletions(-)

-- 
Regards,

Laurent Pinchart