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In-Reply-To: <20190920061800.65sm6jth2afatsvl@gilmour>
From:   Roman Stratiienko <roman.stratiienko@globallogic.com>
Date:   Fri, 20 Sep 2019 23:09:39 +0300
Message-ID: <CAODwZ7vmiBQ87FeGVwxkcZ3DFaGHk8iDCOavNNRw=MO1hFNruA@mail.gmail.com>
Subject: Re: [PATCH] drm/sun4i: Use vi plane as primary
To:     Maxime Ripard <mripard@kernel.org>
Cc:     =?UTF-8?Q?Jernej_=C5=A0krabec?= <jernej.skrabec@siol.net>,
        linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org
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@Jernej =C5=A0krabec @Maxime Ripard

Thanks for your time and valuable suggestions.

Currently I would have to go away from mainline KMS to solve my
(Android) issues, and I hope to get back when I
find mainline-friendly solution for it.

Having no primary layer or zero-buffer primary layer and 4 overlays
could be a universal solution, but  I have not sufficient knowledge in
KMS to bring-up this idea.

On Fri, Sep 20, 2019 at 9:18 AM Maxime Ripard <mripard@kernel.org> wrote:
>
> Hi,
>
> On Thu, Sep 19, 2019 at 11:03:26PM +0300, Roman Stratiienko wrote:
> > Actually, I beleive this is True solution, and current one is wrong.  L=
et
> > me explain why.
> >
> > De2. 0 was designed to match Android hwcomposer hal requirements IMO.
> > You can easily agree with this conclusion by comparing Composer HAL and
> > De2. 0 hardware manuals.
> >
> > I faced at least 4 issues when try to run Android using the mainline ke=
rnel
> > sun8i mixer implementation. Current one, missing pixel formats (my prev=
ious
> > patch), missing plane alpha and rotation properties. I plan to fix it a=
nd
> > also send appropriate solution to the upstream.
> >
> > To achieve optimal UI performance Android requires at least 4 ui layers=
 to
> > make screen composition. Current patch enables 4th plane usable.
>
> Note that you can also get 4 UI planes by enabling more than one UI
> layer per channel. You wouldn't be able to use alpha between each
> plane of a given channel, but we can use a similar trick than what we
> did for the pipes in the sun4i backend.
>
> Maxime


--=20
Best regards,
Roman Stratiienko
Global Logic Inc.