Comment 1 for bug 312549

Doesn't apply always for me. For example changing from Performance to Presentation works properly for me.

The apparently associated KDE bug suggests that this issue is related to DPMS, so please aggregate some information about your graphics hardware:

first run on a terminal
   lspci | grep VGA
now please run
   sudo lspci -v -s 00:02.0
where 00:02.0 needs to be replaced by whatever number the first output started with. Finally please post the output of the last command as comment to this report.

For me it is:
00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller (rev03)
        Subsystem: Dell Device 01bd
        Flags: bus master, fast devsel, latency 0, IRQ 16
        Memory at eff00000 (32-bit, non-prefetchable) [size=512K]
        I/O ports at eff8 [size=8]