Problem: Monitor1 that’s on KVM switch is detected properly on boot and whenever the switch is on Computer1, but temporarily switching to Computer2 causes Monitor1 to be considered Off. When it’s considered Off, the resolution is 1024x768, not 2560x1440, like at boot.
Goal: Computer1 should continue to output to Monitor1 with same config as during boot. Monitor1 should never be considered Off. KVM switching over to Computer2 should not affect display output of Computer1.
KScreen2 is off.
xorg.conf uses Option "ConnectedMonitor" "DFP-0, DFP-2". (DFP-0 is the relevant output.) This should keep Computer1 thinking that Monitor1 is connected, regardless of KVM switch setting, which it does. The problem is that when the KVM switch is set to Computer2, Computer1 thinks the Monitor1 is Off. Off seems to be a different state than Connected. A monitor could be considered Connected, but Off. I’m looking for a way to force Monitor1 to stay the same config as at boot.
xrandr --output DP-0 --mode 2048x1152 works to force DFP-0 to a higher resolution, but for whatever reason, 2560x1440 is no longer a selectable mode. Again, if possible, there’s an Option for xorg.conf to keep monitors On, more than just Connected. Using xrandr is an okay work-around to turn back On the monitor when the KVM switch is on Computer2, but the resolution at boot, 2560x1440, isn’t an available mode once the monitor is considered Off.
Thanks for the help!
Does this help with diagnosing the problem?
xrandr output with Monitor1 and Monitor2. KVM switch is on Computer1, where xrandr is run from…
Screen 0: minimum 8 x 8, current 4480 x 1440, maximum 32767 x 32767
DP-0 connected 2560x1440+0+0 (normal left inverted right x axis y axis) 597mm x 336mm
2560x1440 59.95*+
1920x1200 59.95
1920x1080 60.00
1600x1200 60.00
1280x1024 60.02
1280x960 60.00
1024x768 60.00
800x600 60.32
640x480 59.94
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 connected primary 1920x1200+2560+0 (normal left inverted right x axis y axis) 518mm x 324mm
1920x1200 59.95*+ 59.88
1920x1080 60.00 59.94 50.00 29.97 25.00 23.98
1600x1200 60.00
1280x1024 75.02 60.02
1280x720 60.00 59.94 50.00
1152x864 75.00
1024x768 75.03 60.00
800x600 75.00 60.32
720x576 50.00
720x480 59.94
640x480 75.00 59.94 59.93
DP-3 disconnected (normal left inverted right x axis y axis)
DP-4 disconnected (normal left inverted right x axis y axis)
DP-5 disconnected (normal left inverted right x axis y axis)
DP-6 disconnected (normal left inverted right x axis y axis)
DP-7 disconnected (normal left inverted right x axis y axis)
KVM switch on Computer2… xrandr run from Computer1, which sees Monitor1 as Off and resolution of 1024x768. 2560x1440 is no longer an option for Monitor1 and listed at the very bottom of xrandr output…
Screen 0: minimum 8 x 8, current 4480 x 1440, maximum 32767 x 32767
DP-0 connected 2560x1440+0+0 (normal left inverted right x axis y axis) 597mm x 336mm
1024x768 60.00 +
2048x1152 59.91 59.90
1920x1200 59.95 59.88
1920x1080 59.96 59.93
1792x1344 60.01
1680x1050 59.95 59.88
1600x1200 60.00
1600x900 59.95 59.82
1400x1050 59.98
1400x900 59.96 59.88
1368x768 59.88 59.85
1280x1024 60.02
1280x960 60.00
1280x800 59.91 59.81
1280x720 59.86 59.74
1024x576 59.90 59.82 59.96 59.95
960x600 60.00 59.93
960x540 59.82 59.63 59.99 59.96
896x672 60.01
864x486 59.92 59.57
840x525 60.01 59.88
800x600 60.32 56.25 60.00
800x450 59.95 59.82
700x525 59.98
700x450 59.96 59.88
684x384 59.88 59.85
640x512 60.02
640x480 59.94 60.00
640x400 59.98 59.88
640x360 59.86 59.83
512x384 60.00
512x288 60.00 59.92
480x270 59.82 59.63
432x243 59.92 59.57
400x300 60.32 56.34
320x240 60.05
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 connected primary 1920x1200+2560+0 (normal left inverted right x axis y axis) 518mm x 324mm
1920x1200 59.95*+ 59.88
1920x1080 60.00 59.94 50.00 29.97 25.00 23.98
1600x1200 60.00
1280x1024 75.02 60.02
1280x720 60.00 59.94 50.00
1152x864 75.00
1024x768 75.03 60.00
800x600 75.00 60.32
720x576 50.00
720x480 59.94
640x480 75.00 59.94 59.93
DP-3 disconnected (normal left inverted right x axis y axis)
DP-4 disconnected (normal left inverted right x axis y axis)
DP-5 disconnected (normal left inverted right x axis y axis)
DP-6 disconnected (normal left inverted right x axis y axis)
DP-7 disconnected (normal left inverted right x axis y axis)
2560x1440 (0x21e) 241.500MHz +HSync -VSync
h: width 2560 start 2608 end 2640 total 2720 skew 0 clock 88.79KHz
v: height 1440 start 1443 end 1448 total 1481 clock 59.95Hz
Well, this Option line in Section “Screen” of xorg.conf solves my problem, which is to keep Monitor1 as the same configuration as on boot:
Option "ModeValidation" "NoDFPNativeResolutionCheck,NoVirtualSizeCheck,NoMaxPClkCheck,NoHorizSyncCheck,NoVertRefreshCheck,NoWidthAlignmentCheck"
The monitor stays as 2560x1440.
Unfortunately, this means the problem I’m trying to solve is actually on a remote machine where I’m running x11vnc from. I’m looking for a way to stop x11vnc from polling xrandr after it initially starts. Polling on x11vnc start up is 2560x1440. With KVM switch used to switch to Computer2, then back to Computer1, x11vnc re-polls and sees 1024x768. This should probably be a different subject on the thread, so I’ll start a new one.