Blurry display - disper choosing refresh rate of 59.9 over 60.0

[Sigbjorn Lie]

Dipser chooses 59.9 refresh rate over 60.0, for my primary display, causing this display go blurry.

This is the output when I have set resolution manully using nvidia-settings:
$ xrandr
Screen 0: minimum 8 x 8, current 3840 x 1200, maximum 16384 x 16384
DVI-I-0 disconnected (normal left inverted right x axis y axis)
DVI-I-1 connected 1920x1200+0+0 (normal left inverted right x axis y axis) 518mm x 324mm
   1920x1200 60.0*+ 59.9
   1600x1200 60.0
   1280x1024 75.0 60.0
   1152x864 75.0
   1024x768 75.0 60.0
   800x600 75.0 60.3
   640x480 75.0 59.9
DP-0 connected 1920x1200+1920+0 (normal left inverted right x axis y axis) 518mm x 324mm
   1920x1200 60.0*+
   1600x1200 60.0
   1280x1024 75.0 60.0
   1152x864 75.0
   1024x768 75.0 60.0
   800x600 75.0 60.3
   640x480 75.0 59.9
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
DP-3 disconnected (normal left inverted right x axis y axis)

And this is after running disper:

$ sudo /opt/disper/bin/disper -e -r auto -d auto --plugins=notify,debug -v
Enabled plugins: notify debug
NVidia kernel driver version: 319.32
backend: XRandR
auto-detected displays: DVI-I-1, DP-0
resolutions of DVI-I-1: 640x480, 800x600, 1024x768, 1152x864, 1280x1024, 1600x1200, 1920x1200
resolutions of DP-0: 640x480, 800x600, 1024x768, 1152x864, 1280x1024, 1600x1200, 1920x1200
preferred resolutions for displays: DVI-I-1: 1920x1200, DP-0: 1920x1200
DVI-I-1: available refresh rates for resolution 1920x1200: 59, 59
DVI-I-1: selecting XRandR mode #1: 1920x1200 59Hz
DP-0: selecting XRandR mode #0: 1920x1200 59Hz
Executing hook: /opt/disper/share/disper/hooks/notify.sh -e -r auto -d auto --plugins=notify,debug -v
Executing hook: /opt/disper/share/disper/hooks/debug.sh -e -r auto -d auto --plugins=notify,debug -v
Disper hook environment for stage: switch
  DISPER_BB_RESOLUTION=3840x1200
  DISPER_VERSION=0.3.1
  DISPER_DISPLAYS=DVI_I_1 DP_0
  DISPER_LOG_LEVEL=20
  DISPER_STAGE=switch
  DISPER_LAYOUT=right
  DISPER_RESOLUTION_DVI_I_1=1920x1200
  DISPER_RESOLUTION_DP_0=1920x1200

$ xrandr
Screen 0: minimum 8 x 8, current 3840 x 1200, maximum 16384 x 16384
DVI-I-0 disconnected (normal left inverted right x axis y axis)
DVI-I-1 connected 1920x1200+0+0 (normal left inverted right x axis y axis) 520mm x 320mm
   1920x1200 60.0 + 59.9*
   1600x1200 60.0
   1280x1024 75.0 60.0
   1152x864 75.0
   1024x768 75.0 60.0
   800x600 75.0 60.3
   640x480 75.0 59.9
DP-0 connected 1920x1200+1920+0 (normal left inverted right x axis y axis) 518mm x 324mm
   1920x1200 60.0*+
   1600x1200 60.0
   1280x1024 75.0 60.0
   1152x864 75.0
   1024x768 75.0 60.0
   800x600 75.0 60.3
   640x480 75.0 59.9
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
DP-3 disconnected (normal left inverted right x axis y axis)