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From:   Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Date:   Wed, 8 Sep 2021 11:25:50 +0300
Message-ID: <CAA8EJpp6tj10A0QUR1E75t7BZf2Y3jHUyVNniYhEUd9rXj8Vrg@mail.gmail.com>
Subject: Re: [Freedreno] [PATCH 2/3] drm/msm/dpu1: Add MSM8998 to hw catalog
To:     Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
Cc:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@somainline.org>,
        Rob Clark <robdclark@gmail.com>, Sean Paul <sean@poorly.run>,
        Dave Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Abhinav Kumar <abhinavk@codeaurora.org>,
        Rob Herring <robh+dt@kernel.org>,
        MSM <linux-arm-msm@vger.kernel.org>,
        "open list:DRM PANEL DRIVERS" <dri-devel@lists.freedesktop.org>,
        freedreno <freedreno@lists.freedesktop.org>,
        lkml <linux-kernel@vger.kernel.org>,
        Konrad Dybcio <konrad.dybcio@somainline.org>,
        Marijn Suijten <marijn.suijten@somainline.org>,
        Martin Botka <martin.botka@somainline.org>,
        ~postmarketos/upstreaming@lists.sr.ht, phone-devel@vger.kernel.org,
        paul.bouchara@somainline.org, DTML <devicetree@vger.kernel.org>
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Hi,

On Tue, 7 Sept 2021 at 22:13, Jeffrey Hugo <jeffrey.l.hugo@gmail.com> wrote:
>
> On Wed, Sep 1, 2021 at 12:11 PM AngeloGioacchino Del Regno
> <angelogioacchino.delregno@somainline.org> wrote:
> >
> > Bringup functionality for MSM8998 in the DPU, driver which is mostly
> > the same as SDM845 (just a few variations).
> >
> > Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
>
> I don't seem to see a cover letter for this series.
>
> Eh, there are a fair number of differences between the MDSS versions
> for 8998 and 845.
>
> Probably a bigger question, why extend the DPU driver for 8998, when
> the MDP5 driver already supports it[1]?  The MDP/DPU split is pretty
> dumb, but I don't see a valid reason for both drivers supporting the
> same target/display revision.  IMO, if you want this support in DPU,
> remove it from MDP5.
>
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v5.14&id=d6c7b2284b14c66a268a448a7a8d54f585d38785

I don't think that we should enforce such requirements. Having support
both in MDP5 and DPU would allow one to compare those two drivers,
performance, features, etc.
It might be that all MDP5-supported hardware would be also supported
by DPU, thus allowing us to remove the former driver. But until that
time I'd suggest leaving support in place.

-- 
With best wishes
Dmitry