display port monitor, nothing is display

hi

i use kde
i have a lenovo s430 connected to a samsung display port monitor.
i got a lenovo t450, when i connect display port monitor, kde detect it… but nothing is displayed to the screen

thanks


xrandr -q
Screen 0: minimum 320 x 200, current 4160 x 1440, maximum 8192 x 8192
eDP-1 connected primary 1600x900+2560+0 (normal left inverted right x axis y axis) 309mm x 174mm
   1600x900      60.01*+
   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 connected 2560x1440+0+0 (normal left inverted right x axis y axis) 708mm x 398mm
   2560x1440     59.95*+
   1920x1080     60.00    59.94  
   1680x1050     59.95  
   1600x900      60.00  
   1280x1024     75.02    60.02  
   1440x900      59.89  
   1280x800      59.81  
   1152x864      75.00  
   1280x720      60.00    59.94  
   1024x768      75.03    70.07    60.00  
   832x624       74.55  
   800x600       72.19    75.00    60.32    56.25  
   640x480       75.00    72.81    66.67    60.00    59.94  
   720x400       70.08  
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)

Did you set it up in Configure Desktop - Display Monitor ???

yes,
i used hdmi to dp and that worked…

if i use only dp that work… but same cable work on my other laptop

error

if i use only dp that don’t work… but same cable work on my other laptop