Re: output setup and configuration, what lives where?

[drago01 <drago01 gmail com>]

On Mon, Oct 13, 2014 at 8:53 AM, Dave Airlie <airlied gmail com> wrote:
> Hey,
>
> So I've been looking at 4K monitors that require DP MST and present as
> two screens with some tiling info in the EDID extensions, and I've
> been taking a look at how to integrate these with gnome.
>
> Just to clear things up, I tried to hide these in the kernel, the side
> effects were too messy to cover up, and stuff broke in wierd ways, so
> I've decided to follow Windows and push this up a few levels.
>
> So I've built a kernel property to describe tiles, and passed it
> through X to test, and hacked on mutter 3.10, so
>
> a) windows maximize properly
> b) initial mutter configuration picks a sane config.
>
> (cgit.freedesktop.org/~airlied/mutter - will eventually have it).
>
> Now the question is what else needs changing for this, I know I should
> probably start to target master or least F21 versions and I'll
> probably get to that,
>
> I'm getting the feeling at least,
> gnome-desktop
> and
> gnome-control-center
>
> will need work, control-center will probably need design work so the
> UI doesn't suck for this use-case.
>
> I'm just not sure how things like monitors.xml fit in, who writes this
> file, who reads it,

The file is handled by mutter i.e it reads and writes it see:
https://git.gnome.org/browse/mutter/tree/src/backends/meta-monitor-config.c
(or https://git.gnome.org/browse/mutter/tree/src/core/monitor-config.c?h=gnome-3-10
in 3.10).

> is there
> some stuff talking over dbus here,

Mutter exposes the settings over dbus and works as an abstraction
layer over xrandr / kms (on wayland).

> does gnome-session-daemon get
> involved anywhere etc, so pointers/answers etc all appreciated.

gnome-desktop now uses the dbus api exposed by mutter instead of
xrandr directly. gnome-settings-daemon just uses gnome-desktop

So you have to

1) Update mutter to expose it via dbus
2) Extend GnomeRR in gnome-desktop to expose it to clients like g-s-d
and control-center
3) Add UI for control-center that actually uses it (should talk to
designers about it).