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In-Reply-To: <5dcd850a-280c-c356-32e5-35a4fe089f4e@linaro.org>
From:   Rob Clark <robdclark@gmail.com>
Date:   Sun, 4 Jul 2021 11:17:57 -0700
Message-ID: <CAF6AEGvhu9a5yigu-HZZjHuD34i_DyjC8kteYgh73POeS02xcQ@mail.gmail.com>
Subject: Re: [RFC] Inline rotation support in dpu driver
To:     Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc:     Kalyan Thota <kalyan_t@codeaurora.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        freedreno <freedreno@lists.freedesktop.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Douglas Anderson <dianders@chromium.org>,
        Krishna Manikandan <mkrishn@codeaurora.org>
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On Sun, Jul 4, 2021 at 1:25 AM Dmitry Baryshkov
<dmitry.baryshkov@linaro.org> wrote:
>
> On 03/07/2021 14:32, Kalyan Thota wrote:
> > This change adds support for inline rotation in the dpu driver.
> > When inline rotation is enabled the VIG pipes will directly fetch the image
> > from memory in a rotated fashion
> >
> > Inline rotation has following restrictions
> > 1) Supported only with compressed formats
>
> NV12, which is the only format you declare, is not compressed.

nv12 can be used with the UBWC modifier, fwiw.. we use this in CrOS,
albeit with a hack on the v4l2 side to work around lack of modifier
support in v4l2

BR,
-R

> > 2) max pre rotated height is 1088
> > 3) restrictions with downscaling ratio
> >
> > Queries:
> >
> > 1) Since inline rotation works for fewer pixel formats with specific modifier, how can we provide this information to the compositor so that
> > chrome compositor can choose between overlaying or falling back to GPU. In the patch it fails in the atomic check.
> >
> > 2) If a display composition fails in atomic check due to any of the restrictions in overlays
> > can chrome compositor switch it back to the GPU and re trigger the commit ?
> >
> > posting it as RFC as validation is not complete, please share early comments on this.
> >
> > Kalyan Thota (1):
> >    drm/msm/disp/dpu1: add support for inline rotation in dpu driver
> >
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c | 47 +++++++++----
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h | 20 ++++++
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c      | 93 ++++++++++++++++++++------
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_plane.h      |  2 +
> >   4 files changed, 128 insertions(+), 34 deletions(-)
> >
>
>
> --
> With best wishes
> Dmitry