Second Monitor Not Detected, Displays Underscore 16.04 - Ask Ubuntu

i have gtx 950 connected huge monitor, , motherboard's vga connected 18" dell...which displays things fine during boot (and in windows), time hit ubuntu splash screen, blank console-like screen underscore displayed in top left. other (main) monitor works fine. nvidia binary driver 361.42

i've failed detect display in settings , in nvidia's xserver program to. have tried rebooting , th elike

really use help, hate have resort windows

not sure if it'd helpful worth try

first list detected monitors using

xrandr --current 

this show connected display devices. mine shows this

screen 0: minimum 8 x 8, current 1920 x 1080, maximum 16384 x 16384 lvds-1 connected    1366x768      60.10 +    1360x768      59.80    59.96      1024x768      60.04    60.00      960x720       60.00      928x696       60.05      896x672       60.01      960x600       60.00      960x540       59.99      800x600       60.00    60.32    56.25      840x525       60.01    59.88      800x512       60.17      700x525       59.98      640x512       60.02      720x450       59.89      640x480       60.00    59.94      680x384       59.80    59.96      576x432       60.06      512x384       60.00      400x300       60.32    56.34      320x240       60.05   vga-1 connected primary 1920x1080+0+0 477mm x 268mm    1920x1080     60.00*+    1680x1050     59.95      1280x1024     75.02    60.02      1440x900      59.89      1280x960      60.00      1280x720      60.00      1024x768      75.08    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      720x400       70.08   hdmi-1 disconnected dp-1 disconnected 

if both of monitor shown connected can push output as

xrandr --output vga1 --auto --right-of lvds1 

where vga-1 monitor want set output , lvds-1 monitor working

in case of multiple source providers (i.e motherboard , discrete graphics card) use following list out providers:

xrandr --listproviders 

which may output like

providers: number : 3 provider 0: id: 0x2cd cap: 0x1, source output crtcs: 0 outputs: 0 associated providers: 1 name:nvidia-0 provider 1: id: 0x46 cap: 0x2, sink output crtcs: 3 outputs: 4 associated providers: 1 name:modesetting provider 2: id: 0x46 cap: 0x2, sink output crtcs: 3 outputs: 4 associated providers: 1 name:modesetting 

in above output, provider 1 & 2 displaylink device, , provider 0 default display. need offload displaylink main gpu as:

xrandr --setprovideroutputsource 1 0 xrandr --setprovideroutputsource 2 0 

now can check again available displays , set output them