Creating Monitors on Unused Ports
Shakil Shaikh
sshaikh at hotmail.com
Wed Apr 22 15:35:49 UTC 2020
I'm trying to get my host's display :0 to render more monitors than are connected. This is for remote access purposes[1]. Here's my default xrandr output:
Screen 0: minimum 320 x 200, current 1024 x 768, maximum 16384 x 16384
VGA-1 connected primary 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
1024x768 60.00*
800x600 60.32 56.25
848x480 60.00
640x480 59.94
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)
The closest I've come to achieving what I'm after is with the following minimal config (I can add further modes if required).
########
Section "Monitor"
Identifier "VGA-1"
Option "Ignore"
Option "Enable" "false"
EndSection
Section "Monitor"
Identifier "HDMI-1"
Option "Enable" "true"
Option "Primary"
EndSection
Section "Monitor"
Identifier "HDMI-2"
Option "Enable" "true"
Option "LeftOf" "HDMI-1"
EndSection
########
The xrandr output is now:
#########
Screen 0: minimum 320 x 200, current 2736 x 768, maximum 16384 x 16384
HDMI-1 disconnected primary 1368x768+1368+0 (normal left inverted right x axis y axis) 0mm x 0mm
1368x768 59.88*
1280x800 59.81
1280x720 59.86
1024x768 60.00
1024x576 59.90
960x540 59.63
800x600 60.32
800x450 59.82
700x450 59.88
640x480 59.94
684x384 59.88 59.85
640x400 59.88 59.98
640x360 59.86 59.83
512x384 60.00
512x288 60.00 59.92
480x270 59.63 59.82
400x300 60.32
320x240 60.05
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
HDMI-2 disconnected 1368x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
1368x768 59.88*
1280x800 59.81
1280x720 59.86
1024x768 60.00
1024x576 59.90
960x540 59.63
800x600 60.32
800x450 59.82
700x450 59.88
640x480 59.94
684x384 59.88 59.85
640x400 59.88 59.98
640x360 59.86 59.83
512x384 60.00
512x288 60.00 59.92
480x270 59.63 59.82
400x300 60.32
320x240 60.05
##############
This appears to work well, but the only issue is that the Display Manager of my DE (KDE Plasma) kscreen doesn't think there are any monitors connected, which I suppose is reasonable enough. However arandr appears to detect the displays okay.
My questions then are:
1) Assuming this is an unsupported configuration, am I doing anything incorrect or even dangerous?
2) I appreciate that KDE is outside the scope of Xorg, but what could be kscreen looking for? Can I provide it via the xorg config?
Thanks,
[1] I'm only able to get GL performance from my Intel P4600 IGD when accessing the host display. I've tried virtualGL and it didn't seem to be performant (possible due to my IGD being a lowly P4600). Nomachine does work, but only when set to "mirror" the host display. This is great, except I only have a VGA screen attached, and so can't set my desktop larger than that, even if my client screens (on a Windows machine) are much bigger.
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