Re: [gdm-list] gdm: daemons affecting Xorg display configuration and evdev touch screen calibration

[Björn Gerhart <gerhart posteo de>]

> Am 18.03.2016 um 05:46 schrieb ken <cousin newcultures com>:
>
> On 03/17/2016 07:06 PM, Björn Gerhart wrote:
> > Dear list,
> >
> > I’m using gdm-3.14 with CentOS 7. On my system, I don’t provide a static /etc/X11/xorg.conf. Two displays 
> > are connected, one of the displays is equipped with a touch screen by eGalax, which is compatible to evdev.
> >
> > When running gdm and gnome-shell, which is the default after el7 installation, the displays get arranged 
> > in the style of the formerly „Xinerama“ automatically. So when I move the mouse to the right border of one 
> > display, the cursor will appear on the left border of the other display. Furthermore, the touch screen 
> > gets configured exactly the way as expected - the mouse cursor is located directly under the finger of the 
> > display which is eqipped with the touch screen.
> >
> > Now, when I simply type „xinit“ instead from the active multi-user target (according to formerly „runlevel 
> > 3“), both displays show the same content (mirroring). But I want the simple „xinit“ to behave the same way 
> > like gnome does - for dynamically configuring the displays and evdev behavior.
> >
> > Which are the daemons or the functionality behind the gdm resp. gnome startup mechanism, providing that 
> > behavior? I want xinit to start these separately without gnome-shell, and I wonder how to achieve that.
> >
> > Best - Björn
>
> Unsure if I understand your question, but to find processes and what invokes what, do this:
>
> ps -ef --forest|less
>
> then scroll -- or search -- down to gdm.  You'll see the various processes and their relations.
>
> hth

Hi Ken,

thanks for your quick reply.

I analyzed the running gnome related processes, and tried to isolate the one which is responsible for dynamic 
display integration and configuration. However, when starting "xinit" and then successively starting the 
processes I see from the ps output (without gdm itself), then nothing changes and the two displays just 
continue mirroring (same content on both displays).

So what I'm looking for is the information, how gnome arranges the displays dynamically without providing a 
xorg.conf file.

Because gnome consists of numerous source code files, it's tricky to isolate the relevant parts to look into. 
Therefore, hints which source code files to examine are also welcome.

Maybe this is not the proper mailing list to ask for this kind of information - if so please advise which 
list would be the proper one instead.

Best - Björn