Can't get external monitor working on Lenovo P51 (Quadro M2200)

Hi,

Got new laptop and trying to set up environment with “old” monitor (previously great addition to W540).
Monitor is 22’’ LG with preferred resolution 1680x1050. P51 is on built in display 3840x2160.
What I wanted to achieve is to have
[P51 on 3840x2160][LG on 1680x1050 scaled up to 3320x2100]. That, correct me if I’m wrong, should give me sharp display on LG without blurring on fonts when pixels doesn’t match. Correct?

OS sees P51 screen as eDP-1-1 and LG on DP-1 (connected to mini display port by miniDP<->DVI connector)
What I was doing is:

  1. run as first: xrandr --fb 7680x2160 --output DP-1 --scale-from 3360x2100 --panning 3360x2100+3840+0 --right-of eDP-1-1
    no errors but screen blank.
  2. then I run: nvidia-settings --assign CurrentMetaMode=“DPY-1: nvidia-auto-select @3360x2100, ViewPortOut=1680x1050+0+0, ResamplingMethod=Bilinear,ForceFullCompositionPipeline=On }”

Step 2 been googled out by me and according to:

Sometimes step 2 helps but somehow mouse is jailed in left upper corner with its size (seems to me) 1680x1050. And sometimes doesn’t work making nothing or screwing up (resizing) P51 screen where LG is still blank.

Software is:

  • Linux Mint 18.3
  • kernel 4.13.0-37-generic
  • NVIDIA 384.111

Any advices? I’m playing with xrandr and nvidia-settings first time (first time need to re-scale due to primary display on UHD). Can anyone more experienced with that tell me what I’m doing wrong or how my settings string should look like?