To reproduce (hwinfo see underneath):

1. Start laptop with current kde plasma
2. configure kde (kscreen) to only use external screen (DVI as main output),
internal screen LVDS1 off
3. suspend laptop
4. remove external screen by removing laptop from docking station
5. awake laptop from suspend

==>

6. now the internal screen is active, but dimmed to the lowest brightness. The
kde brightness controls have no effect anymore. The only thing that helps:
reboot. After that the brightness is set right to highest value, and the
controls work again.


hwinfo --gfx --monitor
14: PCI 02.1: 0380 Display controller                           
  [Created at pci.378]
  Unique ID: ruGf.Gsn0zTMyIl3
  SysFS ID: /devices/pci0000:00/0000:00:02.1
  SysFS BusID: 0000:00:02.1
  Hardware Class: graphics card
  Model: "Intel Mobile 4 Series Chipset Integrated Graphics Controller"
  Vendor: pci 0x8086 "Intel Corporation"
  Device: pci 0x2a43 "Mobile 4 Series Chipset Integrated Graphics Controller"
  SubVendor: pci 0x1179 "Toshiba America Info Systems"
  SubDevice: pci 0x000d 
  Revision: 0x07
  Memory Range: 0xc0000000-0xc00fffff (rw,non-prefetchable,disabled)
  Module Alias: "pci:v00008086d00002A43sv00001179sd0000000Dbc03sc80i00"
  Config Status: cfg=no, avail=yes, need=no, active=unknown

26: PCI 02.0: 0300 VGA compatible controller (VGA)
  [Created at pci.378]
  Unique ID: _Znp.lPQO3e3I18E
  SysFS ID: /devices/pci0000:00/0000:00:02.0
  SysFS BusID: 0000:00:02.0
  Hardware Class: graphics card
  Model: "Intel Mobile 4 Series Chipset Integrated Graphics Controller"
  Vendor: pci 0x8086 "Intel Corporation"
  Device: pci 0x2a42 "Mobile 4 Series Chipset Integrated Graphics Controller"
  SubVendor: pci 0x1179 "Toshiba America Info Systems"
  SubDevice: pci 0x000d 
  Revision: 0x07
  Driver: "i915"
  Driver Modules: "i915"
  Memory Range: 0xff400000-0xff7fffff (rw,non-prefetchable)
  Memory Range: 0xe0000000-0xefffffff (ro,non-prefetchable)
  I/O Ports: 0xcff8-0xcfff (rw)
  Memory Range: 0x000c0000-0x000dffff (rw,non-prefetchable,disabled)
  IRQ: 16 (786899 events)
  I/O Ports: 0x3c0-0x3df (rw)
  Module Alias: "pci:v00008086d00002A42sv00001179sd0000000Dbc03sc00i00"
  Driver Info #0:
    Driver Status: i915 is active
    Driver Activation Cmd: "modprobe i915"
  Config Status: cfg=no, avail=yes, need=no, active=unknown

28: None 00.0: 10002 LCD Monitor
  [Created at monitor.125]
  Unique ID: rdCR.HWxGBMIb4T1
  Parent ID: _Znp.lPQO3e3I18E
  Hardware Class: monitor
  Model: "LG ELECTRONICS L1953TR "
  Vendor: GSM "LG ELECTRONICS"
  Device: eisa 0x4b44 "L1953TR "
  Resolution: 720x400@70Hz
  Resolution: 640x480@60Hz
  Resolution: 640x480@75Hz
  Resolution: 800x600@60Hz
  Resolution: 800x600@75Hz
  Resolution: 832x624@75Hz
  Resolution: 1024x768@60Hz
  Resolution: 1024x768@75Hz
  Resolution: 640x480@75Hz
  Resolution: 800x600@75Hz
  Resolution: 1024x768@75Hz
  Resolution: 1280x1024@60Hz
  Size: 338x270 mm
  Year of Manufacture: 2008
  Week of Manufacture: 5
  Detailed Timings #0:
     Resolution: 1280x1024
     Horizontal: 1280 1328 1440 1688 (+48 +160 +408) +hsync
       Vertical: 1024 1025 1028 1066 (+1 +4 +42) +vsync
    Frequencies: 108.00 MHz, 63.98 kHz, 60.02 Hz
  Driver Info #0:
    Max. Resolution: 1280x1024
    Vert. Sync Range: 56-75 Hz
    Hor. Sync Range: 30-71 kHz
    Bandwidth: 108 MHz
  Config Status: cfg=new, avail=yes, need=no, active=unknown
  Attached to: #26 (VGA compatible controller)