Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
In-Reply-To: <d4ae26685ad75bd2dde3c3c3b7d086fb544347cc.1516617243.git-series.maxime.ripard@free-electrons.com>
References: <cover.9e7b6a702e4d90a13d08fbe3b0a319cbf4db687f.1516617243.git-series.maxime.ripard@free-electrons.com>
 <d4ae26685ad75bd2dde3c3c3b7d086fb544347cc.1516617243.git-series.maxime.ripard@free-electrons.com>
From:   Chen-Yu Tsai <wens@csie.org>
Date:   Mon, 29 Jan 2018 10:22:54 +0800
Message-ID: <CAGb2v662Qx6nY3Tgvnh=CRMoSDsFwNEiZwW+X8YuN8zMaNwLgw@mail.gmail.com>
Subject: Re: [PATCH v2 16/19] drm/sun4i: backend: Assign the pipes automatically
To:     Maxime Ripard <maxime.ripard@free-electrons.com>
Cc:     Daniel Vetter <daniel.vetter@intel.com>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Sean Paul <seanpaul@chromium.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        thomas@vitsch.nl
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, Jan 22, 2018 at 6:35 PM, Maxime Ripard
<maxime.ripard@free-electrons.com> wrote:
> Since we now have a way to enforce the zpos, check for the number of alpha
> planes, the only missing part is to assign our pipe automatically instead
> of hardcoding it.
>
> The algorithm is quite simple, but requires two iterations over the list of
> planes.
>
> In the first one (which is the same one that we've had to check for alpha,
> the frontend usage, and so on), we order the planes by their zpos.
>
> We can then do a second iteration over that array by ascending zpos
> starting with the pipe 0. When and if we encounter our alpha plane, we put
> it and all the other subsequent planes in the second pipe.
>
> And since we have runtime checks and pipe assignments now, we can just
> remove the static declaration of the planes we used to have.

It would be slightly better if you could split this out into a separate
patch. It's not immediately obvious to others that the changes to
sun4i_layer.c are self-contained, while the change to sun4i_layer.h
is part of the new pipeline tracking thing. Plus I think the way you
structured everything means it won't break if you split it out.

Reviewed-by: Chen-Yu Tsai <wens@csie.org>