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Im using Fedora 24 with 2 additional non HDPI dell monitors with my HDPI laptop (using thunderbolt 3 and daisy chaining the monitors with DP1.2)

I am trying to get the 3 monitors to display nicely with sizing. So far I've managed to get the laptop and 2nd monitor working correctly with the following command:

 xrandr --output eDP-1 --auto --output DP-1-8 --auto --panning 3840x2400+3840+0 --scale 2x2 --right-of eDP-1

however I can't seem to get the 3rd monitor to display anything useful, attempting with this command xrandr --output eDP-1 --auto --output DP-1-8 --auto --panning 3840x2400+3840+0 --scale 2x2 --right-of eDP-1 --output DP-1-1-8 --auto --panning 3840x2400+3840+0 --right-of DP-1-8 has resulted in the 3rd monitor tracking part of the second screen very zoomed in. I think I myust have the scale/panning off.

Can anyone help me get this set up corerctly?

see display setup below:

$ xrandr
Screen 0: minimum 320 x 200, current 7680 x 2400, maximum 8192 x 8192
eDP-1 connected primary 3840x2160+0+0 (normal left inverted right x axis y axis) 346mm x 194mm
   3840x2160     60.00*+
   2048x1536     60.00  
   1920x1440     60.00  
   1856x1392     60.01  
   1792x1344     60.01  
   1600x1200     60.00  
   1400x1050     59.98  
   1280x1024     60.02  
   1280x960      60.00  
   1024x768      60.04    60.00  
   960x720       60.00  
   928x696       60.05  
   896x672       60.01  
   800x600       60.00    60.32    56.25  
   700x525       59.98  
   640x512       60.02  
   640x480       60.00    59.94  
   512x384       60.00  
   400x300       60.32    56.34  
   320x240       60.05  
DP-1 disconnected (normal left inverted right x axis y axis)
HDMI-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
HDMI-2 disconnected (normal left inverted right x axis y axis)
DP-1-8 connected 3840x2400+3840+0 (normal left inverted right x axis y axis) 518mm x 324mm panning 3840x2400+3840+0
   1920x1200     59.95*+
   1920x1080     60.00    50.00    59.94    30.00    25.00    24.00    29.97    23.98  
   1600x1200     60.00  
   1280x1024     75.02    60.02  
   1152x864      75.00  
   1280x720      60.00    50.00    59.94  
   1024x768      75.03    60.00  
   800x600       75.00    60.32  
   720x576       50.00  
   720x480       60.00    59.94  
   640x480       75.00    60.00    59.94  
   720x400       70.08  
DP-1-1-8 connected 3840x2400+3840+0 (normal left inverted right x axis y axis) 518mm x 324mm panning 3840x2400+3840+0
   1920x1200     59.95*+
   1920x1080     60.00    50.00    59.94    30.00    25.00    24.00    29.97    23.98  
   1600x1200     60.00  
   1280x1024     75.02    60.02  
   1152x864      75.00  
   1280x720      60.00    50.00    59.94  
   1024x768      75.03    60.00  
   800x600       75.00    60.32  
   720x576       50.00  
   720x480       60.00    59.94  
   640x480       75.00    60.00    59.94  
   720x400       70.08  
DP-1-1-1 disconnected (normal left inverted right x axis y axis)
DP-1-1 disconnected (normal left inverted right x axis y axis)
  • What graphics card/chip? Are you sure you can actually use 3 monitors at the same time? Many card/chips only support two "crtcs" or "pipes", which means at best the 3rd monitor can display something similar to one of the other monitors. – dirkt Oct 12 '16 at 15:44
  • Pretty sure it can, but maybe you would know: lspci | grep -i graphics 00:02.0 VGA compatible controller: Intel Corporation HD Graphics 530 (rev 06) – Ben Flowers Oct 12 '16 at 15:52
  • Ok, Intel. Do xrandr --listproviders to see the number of your crtcs (= number of monitors with independent image), and xrandr --verbose to see how they are assigned. – dirkt Oct 12 '16 at 16:16
  • xrandr --listproviders Providers: number : 2 Provider 0: id: 0x79 cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 3 outputs: 9 associated providers: 1 name:modesetting Provider 1: id: 0x3f cap: 0x5, Source Output, Source Offload crtcs: 0 outputs: 0 associated providers: 1 name:modesettin – Ben Flowers Oct 12 '16 at 17:14
  • xrandr --verbose was too long, the results are here pastebin.com/ZazKYaQm – Ben Flowers Oct 12 '16 at 17:19
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I'm not very familiar with xrandr that's why I usually would start with a simple fixed setup in /etc/X11/xorg.conf, like this for your case:

Section "Monitor"
  Identifier "ONE"
  Option "PreferredMode"  "3840x2160"
  Option "Position" "0 0"
  Option "Primary" "true"
EndSection

Section "Monitor"
  Identifier "TWO"
  Option "PreferredMode"  "1920x1200"
  Option "Position" "3840 0"
  Option "RightOf" "ONE"
  Option "Primary" "true"
EndSection

Section "Monitor"
  Identifier "THREE"
  Option "PreferredMode"  "1920x1200"
  Option "Position" "5760 0"
  Option "RightOf" "TWO"
  Option "Primary" "true"
EndSection

Section "Device"
  Identifier  "intel-id"
  Driver "intel"
  Option "monitor-eDP-1" "ONE"
  Option "monitor-DP-1-8" "TWO"
  Option "monitor-DP-1-1-8" "THREE"
EndSection

Restart X server, and if ok, try to add the other panning and scale options etc.

At the and you may try to translate the xorg.conf back into a xrand command line. I know actually it would be better to do it the other way around but this way is easier for me.

  • I did this, logged out. Then i was completely unable to log in? Had to start a Wayland session and then delete this file to be able to log in. – Ben Flowers Oct 12 '16 at 14:14
  • Oops maybe the Driver "intel" is wrong?Jjust login on the console "crtl-alt-F2" and remove the file. – rudimeier Oct 12 '16 at 14:23
  • Done that idea how to work out what Driver i need? – Ben Flowers Oct 12 '16 at 15:55
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xrandr --output eDP-1 --auto --output DP-1-8 --auto --panning 3840x2400+3840+0 --scale 2x2 --right-of eDP-1 --output DP-1-1-8 --auto --panning 3840x2400+ 3840 +0 --right-of DP-1-8

Is that value correct? Your first screen will start at x = 0, second at x = 3840, and third at x = 3840 basically displaying same content as 2nd one.

Try:

xrandr --output eDP-1 --auto --output DP-1-8 --auto --panning 3840x2400+3840+0 --scale 2x2 --right-of eDP-1 --output DP-1-1-8 --auto --panning 3840x2400+ 7680 +0 --right-of DP-1-8

Then 3rd one will start just after 2nd one ends.

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