Running X with 2 separate displays on Debian 10 (Buster)

[Böszörményi Zoltán]

2020. 01. 08. 11:30 keltezéssel, Thomas Fazekas írta:
> Dear all,
> 
> I'm sitting in front of a brand new Debian Buster install with 2 monitor setup (the one 
> fro the laptop and a main screen).
> Both are working well, in (what I believe is called) xinerama mode, meaning I have wide 
> desktop of  3840 x 1080 size.
> 
> Now what I would like to have is (I believe) 2 separate displays. I understand that this 
> would come with the limitation that I won't be able to drag windows/applications between 
> the screens.


Something like this should work for you, too:

Section "Monitor"
         Identifier      "Monitor-DP1"
         Option          "AutoServerLayout" "on"
         Option          "Rotate" "normal"
EndSection

Section "Monitor"
         Identifier      "Monitor-VGA1"
         Option          "AutoServerLayout" "on"
         Option          "Rotate" "normal"
EndSection

Section "Device"
         Identifier      "Intel0"
         Driver          "intel"
         BusID           "PCI:0:2:0"
         Screen          0
         Option          "AccelMethod"  "sna"
         Option          "Monitor-DP1" "DP1"
         Option          "ZaphodHeads" "1:DP1"
         Option          "TearFree" "on"
EndSection

Section "Device"
         Identifier      "Intel1"
         Driver          "intel"
         BusID           "PCI:0:2:0"
         Screen          1
         Option          "AccelMethod"  "sna"
         Option          "Monitor-VGA1" "VGA1"
         Option          "ZaphodHeads" "0:VGA1"
         Option          "TearFree" "on"
EndSection

Section "Screen"
         Identifier      "SCREEN"
         Option          "AutoServerLayout" "on"
         Device          "Intel0"
         Monitor         "Monitor-DP1"
         SubSection      "Display"
                 Modes   "1024x768"
                 Depth   24
         EndSubSection
EndSection

Section "Screen"
         Identifier      "SCREEN1"
         Option          "AutoServerLayout" "on"
         Device          "Intel1"
         Monitor         "Monitor-VGA1"
         SubSection      "Display"
                 Modes   "1024x768"
                 Depth   24
         EndSubSection
EndSection

Section "ServerLayout"
         Identifier      "LAYOUT"
         Option          "AutoServerLayout" "on"
         Screen          0 "SCREEN"
         Screen          1 "SCREEN1" RightOf "SCREEN"
EndSection

Now, the ZaphodHeads setting is something you need to
set up for your own machine, since vendors can wire
up video outputs differently. Look for messages like this
in /var/log/Xorg.0.log:

[ 42699.692] (II) intel(0): switch to mode 1024x768 at 60.0 on DP1 using pipe 0, position (0, 
0), rotation normal, reflection none

There will be one such line for every connected video output
but autodetected when there's no explicit configuration.
You need to specify the pipe number along with the output name
in Option "ZaphodHeads" for every Device section in the config.

Also, BusID should match your machine, not the above quoted example.

Another thing is that with using the Intel driver, the outputs
are called DPI1, VGA1 and so on, with the output type and number
written as you see. With the modesetting driver, they become
DPI-1, VGA-1.

Best regards,
Zoltán Böszörményi


> 
> My hardware  (inxi -GxxS) :
> System:    Host: thobian Kernel: 4.19.0-6-amd64 x86_64 bits: 64 compiler: gcc v: 8.3.0 
> Desktop: Cinnamon 3.8.8 dm: startx
>             Distro: Debian GNU/Linux 10 (buster)
> Graphics:  Device-1: Intel UHD Graphics 620 vendor: Lenovo driver: i915 v: kernel bus ID: 
> 00:02.0 chip ID: 8086:5917
>             Display: tty server: X.Org 1.20.4 driver: modesetting unloaded: fbdev,vesa
>             resolution: 1920x1080~60Hz, 1920x1080~60Hz
>             OpenGL: renderer: Mesa DRI Intel UHD Graphics 620 (Kabylake GT2) v: 4.5 Mesa 
> 18.3.6 compat-v: 3.0
>             direct render: Yes
> 
> As far as I'm concerned there is currently no xorg.conf configuration file that  would 
> store any X config, everything comes from the "auto config"
> 
> Thanks in advance
> 
> _______________________________________________
> xorg at lists.x.org: X.Org support
> Archives: http://lists.freedesktop.org/archives/xorg
> Info: https://lists.x.org/mailman/listinfo/xorg
> Your subscription address: %(user_address)s
>