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

[Jacopo Mondi]

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 ?

> 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[]

> 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(-)
>
> --
> 2.34.1
>