Created attachment 106583 [details] Screenshot of plasma not detecting full display scaled When rescaling one monitor in a dual-head setup, plasma does not detect to new display area and leave it blank (black). In this sample the display on the left is a 1920x1080 and the one on the right is 2560x1440 (notebook). This is the xrandr line to set it up: xrandr --output DP-2 --mode 1920x1080 --scale 1.5x1.5 --output DP-0 --pos 2880x300 I will post the output of xrandr --verbose in the next comment. Attached is a screenshot of the effect. It is important to note that this would not be necessary if the Scale (in System Settings -> Display and Monitor -> Scale Display) accepted values below 1.
raul@nostromo:~$ xrandr --verbose Screen 0: minimum 8 x 8, current 5440 x 1740, maximum 32767 x 32767 HDMI-0 disconnected (normal left inverted right x axis y axis) Identifier: 0x1be Timestamp: 594350 Subpixel: unknown Clones: CRTCs: 0 1 2 3 Transform: 1.000000 0.000000 0.000000 0.000000 1.000000 0.000000 0.000000 0.000000 1.000000 filter: CscMatrix: 65536 0 0 0 0 65536 0 0 0 0 65536 0 BorderDimensions: 4 supported: 4 Border: 0 0 0 0 range: (0, 65535) SignalFormat: TMDS supported: TMDS ConnectorType: HDMI ConnectorNumber: 2 _ConnectorLocation: 2 DP-0 connected primary 2560x1440+2880+300 (0x1c0) normal (normal left inverted right x axis y axis) 382mm x 214mm Identifier: 0x1bf Timestamp: 594350 Subpixel: unknown Gamma: 1.0:1.0:1.0 Brightness: 1.0 Clones: CRTC: 0 CRTCs: 0 1 2 3 Transform: 1.000000 0.000000 0.000000 0.000000 1.000000 0.000000 0.000000 0.000000 1.000000 filter: CscMatrix: 65536 0 0 0 0 65536 0 0 0 0 65536 0 Backlight: 100 range: (0, 100) EDID: 00ffffffffffff0006af9610e426e270 001a0104a52615780230c0a556559e26 0d4f5600000001010101010101010101 01010101010128c300a0a0a05a503020 35007ed61000001828c300a0a0a05456 302035007ed610000018000000fe0041 554f0a202020202020202020000000fe 004231373351544e30312e30200a0060 BorderDimensions: 4 supported: 4 Border: 0 0 0 0 range: (0, 65535) SignalFormat: DisplayPort supported: DisplayPort ConnectorType: Panel ConnectorNumber: 3 _ConnectorLocation: 3 2560x1440 (0x1c0) 499.600MHz -HSync -VSync *current +preferred h: width 2560 start 2608 end 2640 total 2720 skew 0 clock 183.68KHz v: height 1440 start 1443 end 1448 total 1530 clock 120.05Hz 2560x1440 (0x1c1) 499.600MHz -HSync -VSync h: width 2560 start 2608 end 2640 total 2720 skew 0 clock 183.68KHz v: height 1440 start 1443 end 1448 total 3060 clock 60.02Hz DP-1 disconnected (normal left inverted right x axis y axis) Identifier: 0x1c2 Timestamp: 594350 Subpixel: unknown Clones: CRTCs: 0 1 2 3 Transform: 1.000000 0.000000 0.000000 0.000000 1.000000 0.000000 0.000000 0.000000 1.000000 filter: CscMatrix: 65536 0 0 0 0 65536 0 0 0 0 65536 0 BorderDimensions: 4 supported: 4 Border: 0 0 0 0 range: (0, 65535) SignalFormat: DisplayPort supported: DisplayPort ConnectorType: DisplayPort ConnectorNumber: 4 _ConnectorLocation: 4 DP-2 connected 2880x1620+0+0 (0x1c4) normal (normal left inverted right x axis y axis) 477mm x 268mm Identifier: 0x1c3 Timestamp: 594350 Subpixel: unknown Gamma: 1.0:1.0:1.0 Brightness: 1.0 Clones: CRTC: 1 CRTCs: 0 1 2 3 Transform: 1.500000 0.000000 0.000000 0.000000 1.500000 0.000000 0.000000 0.000000 1.000000 filter: CscMatrix: 65536 0 0 0 0 65536 0 0 0 0 65536 0 EDID: 00ffffffffffff0010ac72a04d5a5731 1616010380301b78ea01f5a257529f27 0a5054a54b00714f8180d1c001010101 010101010101023a801871382d40582c 4500dd0c1100001e000000ff004e3846 334d32354f31575a4d0a000000fc0044 454c4c204532323131480a20000000fd 00384c1e5311000a202020202020001f BorderDimensions: 4 supported: 4 Border: 0 0 0 0 range: (0, 65535) SignalFormat: TMDS supported: TMDS ConnectorType: DisplayPort ConnectorNumber: 4 _ConnectorLocation: 4 1920x1080 (0x1c4) 148.500MHz +HSync +VSync *current +preferred h: width 1920 start 2008 end 2052 total 2200 skew 0 clock 67.50KHz v: height 1080 start 1084 end 1089 total 1125 clock 60.00Hz 1280x1024 (0x1c5) 135.000MHz +HSync +VSync h: width 1280 start 1296 end 1440 total 1688 skew 0 clock 79.98KHz v: height 1024 start 1025 end 1028 total 1066 clock 75.02Hz 1280x1024 (0x1c6) 108.000MHz +HSync +VSync h: width 1280 start 1328 end 1440 total 1688 skew 0 clock 63.98KHz v: height 1024 start 1025 end 1028 total 1066 clock 60.02Hz 1152x864 (0x1c7) 108.000MHz +HSync +VSync h: width 1152 start 1216 end 1344 total 1600 skew 0 clock 67.50KHz v: height 864 start 865 end 868 total 900 clock 75.00Hz 1024x768 (0x1c8) 78.750MHz +HSync +VSync h: width 1024 start 1040 end 1136 total 1312 skew 0 clock 60.02KHz v: height 768 start 769 end 772 total 800 clock 75.03Hz 1024x768 (0x1c9) 65.000MHz -HSync -VSync h: width 1024 start 1048 end 1184 total 1344 skew 0 clock 48.36KHz v: height 768 start 771 end 777 total 806 clock 60.00Hz 800x600 (0x1ca) 49.500MHz +HSync +VSync h: width 800 start 816 end 896 total 1056 skew 0 clock 46.88KHz v: height 600 start 601 end 604 total 625 clock 75.00Hz 800x600 (0x1cb) 40.000MHz +HSync +VSync h: width 800 start 840 end 968 total 1056 skew 0 clock 37.88KHz v: height 600 start 601 end 605 total 628 clock 60.32Hz 640x480 (0x1cc) 31.500MHz -HSync -VSync h: width 640 start 656 end 720 total 840 skew 0 clock 37.50KHz v: height 480 start 481 end 484 total 500 clock 75.00Hz 640x480 (0x1cd) 25.175MHz -HSync -VSync h: width 640 start 656 end 752 total 800 skew 0 clock 31.47KHz v: height 480 start 490 end 492 total 525 clock 59.94Hz DP-3 disconnected (normal left inverted right x axis y axis) Identifier: 0x1ce Timestamp: 594350 Subpixel: unknown Clones: CRTCs: 0 1 2 3 Transform: 1.000000 0.000000 0.000000 0.000000 1.000000 0.000000 0.000000 0.000000 1.000000 filter: CscMatrix: 65536 0 0 0 0 65536 0 0 0 0 65536 0 BorderDimensions: 4 supported: 4 Border: 0 0 0 0 range: (0, 65535) SignalFormat: DisplayPort supported: DisplayPort ConnectorType: DisplayPort ConnectorNumber: 5 _ConnectorLocation: 5 DP-4 disconnected (normal left inverted right x axis y axis) Identifier: 0x1cf Timestamp: 594350 Subpixel: unknown Clones: CRTCs: 0 1 2 3 Transform: 1.000000 0.000000 0.000000 0.000000 1.000000 0.000000 0.000000 0.000000 1.000000 filter: CscMatrix: 65536 0 0 0 0 65536 0 0 0 0 65536 0 BorderDimensions: 4 supported: 4 Border: 0 0 0 0 range: (0, 65535) SignalFormat: TMDS supported: TMDS ConnectorType: DisplayPort ConnectorNumber: 5 _ConnectorLocation: 5
The display card is a NVidia. Driver: nvidia-375 Kubuntu (ubuntu + kubuntu backports) 17.04 About the Screenshot, the black area in the left is where plasma fails to see and use. Note the "add widgets" button on the top right, not being in the top right. Also note that I am able to use this space fine, as I placed a konsole terminal in there. The black area in the top of the right display is correct, as there is an height offset between the two displays to match the physical position.
>It is important to note that this would not be necessary if the Scale (in System Settings -> Display and Monitor -> Scale Display) accepted values below 1. How would that help?
Dualhead is no longer explicitly supported, sorry.