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Message-ID: <febb665904a9c3c680363be8ea83f243ccd09cb7.camel@pengutronix.de>
Subject: Re: [PATCH v5 0/4] Add support for iMX8MQ Display Controller
 Subsystem
From:   Lucas Stach <l.stach@pengutronix.de>
To:     Daniel Vetter <daniel@ffwll.ch>,
        Philipp Zabel <p.zabel@pengutronix.de>
Cc:     Laurentiu Palcu <laurentiu.palcu@oss.nxp.com>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        Laurentiu Palcu <laurentiu.palcu@nxp.com>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        devicetree <devicetree@vger.kernel.org>,
        Guido =?ISO-8859-1?Q?G=FCnther?= <agx@sigxcpu.org>,
        lukas@mntmn.com,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Date:   Fri, 17 Jul 2020 11:12:39 +0200
In-Reply-To: <CAKMK7uGsveS+cwxiTq7BGrB1OcE_ff9bAxgSFDMUSmS7gRLJ7g@mail.gmail.com>
References: <20200709164736.18291-1-laurentiu.palcu@oss.nxp.com>
         <3c03afff3256ec36e12b9d9408830fbb4853f982.camel@pengutronix.de>
         <CAKMK7uGsveS+cwxiTq7BGrB1OcE_ff9bAxgSFDMUSmS7gRLJ7g@mail.gmail.com>
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Am Freitag, den 17.07.2020, 10:59 +0200 schrieb Daniel Vetter:
> On Fri, Jul 17, 2020 at 10:18 AM Lucas Stach <l.stach@pengutronix.de> wrote:
> > Hi Laurentiu,
> > 
> > Am Donnerstag, den 09.07.2020, 19:47 +0300 schrieb Laurentiu Palcu:
> > > From: Laurentiu Palcu <laurentiu.palcu@nxp.com>
> > > 
> > > Hi,
> > > 
> > > This patchset adds initial DCSS support for iMX8MQ chip. Initial support
> > > includes only graphics plane support (no video planes), no HDR10 capabilities,
> > > no graphics decompression (only linear, tiled and super-tiled buffers allowed).
> > > 
> > > Support for the rest of the features will be added incrementally, in subsequent
> > > patches.
> > > 
> > > The patchset was tested with both HDP driver (in the downstream tree) and the upstream
> > > MIPI-DSI driver (with a couple of patches on top, to make it work correctly with DCSS).
> > 
> > I think the series (minus 3/5 and minor correction to the DT binding)
> > is fine to go in now. So just some formal questions: are you going to
> > maintain this driver in upstream? If so we should add a MAINTAINERS
> > entry to that effect. I can offer to act as a reviewer in this case.
> > 
> > How do you intend to merge this? IMO pushing this through drm-misc
> > seems like the right thing to do. If you agree I can help you get this
> > applied. If you are going to maintain the driver on your own, I think
> > you should then apply for commit rights to drm-misc.
> 
> drm/imx isn't listed yet as under the drm-misc umbrella, maybe we
> should put the entire collective of imx drivers under drm-misc? Or
> maybe it's just an oversight that the git repo isn't specified in the
> MAINTAINERS entry. Also maybe we should add the pengutronix kernel
> team alias there too?

drm/imx was exclusively the IPUv3 up until now, which is in fact
maintained outside of drm-misc in its own git tree. This has worked
quite well in the past so even though IPUv3 doesn't see a lot of churn
these days the motivation to change anything to this workflow is quite
low. And yes, the git tree is missing from the MAINTAINERS entry.

For the DCSS driver, if it's going to be maintained by NXP, I figured
it might be easier for Laurentiu to push things into drm-misc than set
up a separate public git tree. But IMHO that's fully up to him to
decide.

Regards,
Lucas

> -Daniel
> 
> 
> > Regards,
> > Lucas
> > 
> > > Thanks,
> > > Laurentiu
> > > 
> > > Changes in v5:
> > >  * Rebased to latest;
> > >  * Took out component framework support and made it a separate patch so
> > >    that people can still test with HDP driver, which makes use of it.
> > >    But the idea is to get rid of it once HDP driver's next versions
> > >    will remove component framework as well;
> > >  * Slight improvement to modesetting: avoid cutting off the pixel clock
> > >    if the new mode and the old one are equal. Also, in this case, is
> > >    not necessary to wait for DTG to shut off. This would allow to switch
> > >    from 8b RGB to 12b YUV422, for example, with no interruptions (at least
> > >    from DCSS point of view);
> > >  * Do not fire off CTXLD when going to suspend, unless it still has
> > >    entries that need to be committed to DCSS;
> > >  * Addressed Rob's comments on bindings;
> > > 
> > > Changes in v4:
> > >  * Addressed Lucas and Philipp's comments:
> > >    * Added DRM_KMS_CMA_HELPER dependency in Kconfig;
> > >    * Removed usage of devm_ functions since I'm already doing all the
> > >      clean-up in the submodules_deinit();
> > >    * Moved the drm_crtc_arm_vblank_event() in dcss_crtc_atomic_flush();
> > >    * Removed en_completion variable from dcss_crtc since this was
> > >      introduced mainly to avoid vblank timeout warnings which were fixed
> > >      by arming the vblank event in flush() instead of begin();
> > >    * Removed clks_on and irq_enabled flags since all the calls to
> > >      enabling/disabling clocks and interrupts were balanced;
> > >    * Removed the custom atomic_commit callback and used the DRM core
> > >      helper and, in the process, got rid of a workqueue that wasn't
> > >      necessary anymore;
> > >    * Fixed some minor DT binding issues flagged by Philipp;
> > >    * Some other minor changes suggested by Lucas;
> > >  * Removed YUV formats from the supported formats as these cannot work
> > >    without the HDR10 module CSCs and LUTs. Will add them back when I
> > >    will add support for video planes;
> > > 
> > > Changes in v3:
> > >  * rebased to latest linux-next and made it compile as drmP.h was
> > >    removed;
> > >  * removed the patch adding the VIDEO2_PLL clock. It's already applied;
> > >  * removed an unnecessary 50ms sleep in the dcss_dtg_sync_set();
> > >  * fixed a a spurious hang reported by Lukas Hartmann and encountered
> > >    by me several times;
> > >  * mask DPR and DTG interrupts by default, as they may come enabled from
> > >    U-boot;
> > > 
> > > Changes in v2:
> > >  * Removed '0x' in node's unit-address both in DT and yaml;
> > >  * Made the address region size lowercase, to be consistent;
> > >  * Removed some left-over references to P010;
> > >  * Added a Kconfig dependency of DRM && ARCH_MXC. This will also silence compilation
> > >    issues reported by kbuild for other architectures;
> > > 
> > > Laurentiu Palcu (5):
> > >   drm/imx: compile imx directory by default
> > >   drm/imx: Add initial support for DCSS on iMX8MQ
> > >   drm/imx/dcss: add component framework functionality
> > >   dt-bindings: display: imx: add bindings for DCSS
> > >   arm64: dts: imx8mq: add DCSS node
> > > 
> > >  .../bindings/display/imx/nxp,imx8mq-dcss.yaml |  84 ++
> > >  arch/arm64/boot/dts/freescale/imx8mq.dtsi     |  23 +
> > >  drivers/gpu/drm/Makefile                      |   2 +-
> > >  drivers/gpu/drm/imx/Kconfig                   |   2 +
> > >  drivers/gpu/drm/imx/Makefile                  |   1 +
> > >  drivers/gpu/drm/imx/dcss/Kconfig              |   9 +
> > >  drivers/gpu/drm/imx/dcss/Makefile             |   6 +
> > >  drivers/gpu/drm/imx/dcss/dcss-blkctl.c        |  70 ++
> > >  drivers/gpu/drm/imx/dcss/dcss-crtc.c          | 219 +++++
> > >  drivers/gpu/drm/imx/dcss/dcss-ctxld.c         | 424 +++++++++
> > >  drivers/gpu/drm/imx/dcss/dcss-dev.c           | 314 +++++++
> > >  drivers/gpu/drm/imx/dcss/dcss-dev.h           | 177 ++++
> > >  drivers/gpu/drm/imx/dcss/dcss-dpr.c           | 562 ++++++++++++
> > >  drivers/gpu/drm/imx/dcss/dcss-drv.c           | 183 ++++
> > >  drivers/gpu/drm/imx/dcss/dcss-dtg.c           | 409 +++++++++
> > >  drivers/gpu/drm/imx/dcss/dcss-kms.c           | 185 ++++
> > >  drivers/gpu/drm/imx/dcss/dcss-kms.h           |  43 +
> > >  drivers/gpu/drm/imx/dcss/dcss-plane.c         | 405 +++++++++
> > >  drivers/gpu/drm/imx/dcss/dcss-scaler.c        | 826 ++++++++++++++++++
> > >  drivers/gpu/drm/imx/dcss/dcss-ss.c            | 180 ++++
> > >  20 files changed, 4123 insertions(+), 1 deletion(-)
> > >  create mode 100644 Documentation/devicetree/bindings/display/imx/nxp,imx8mq-dcss.yaml
> > >  create mode 100644 drivers/gpu/drm/imx/dcss/Kconfig
> > >  create mode 100644 drivers/gpu/drm/imx/dcss/Makefile
> > >  create mode 100644 drivers/gpu/drm/imx/dcss/dcss-blkctl.c
> > >  create mode 100644 drivers/gpu/drm/imx/dcss/dcss-crtc.c
> > >  create mode 100644 drivers/gpu/drm/imx/dcss/dcss-ctxld.c
> > >  create mode 100644 drivers/gpu/drm/imx/dcss/dcss-dev.c
> > >  create mode 100644 drivers/gpu/drm/imx/dcss/dcss-dev.h
> > >  create mode 100644 drivers/gpu/drm/imx/dcss/dcss-dpr.c
> > >  create mode 100644 drivers/gpu/drm/imx/dcss/dcss-drv.c
> > >  create mode 100644 drivers/gpu/drm/imx/dcss/dcss-dtg.c
> > >  create mode 100644 drivers/gpu/drm/imx/dcss/dcss-kms.c
> > >  create mode 100644 drivers/gpu/drm/imx/dcss/dcss-kms.h
> > >  create mode 100644 drivers/gpu/drm/imx/dcss/dcss-plane.c
> > >  create mode 100644 drivers/gpu/drm/imx/dcss/dcss-scaler.c
> > >  create mode 100644 drivers/gpu/drm/imx/dcss/dcss-ss.c
> > > 
> > 
> > _______________________________________________
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> > dri-devel@lists.freedesktop.org
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> 
>