Originally Posted by sconf

I have the filter-brightness-simple now working, at least most of the time. Every now and then I get the black screen effect when double-tapping the lock screen (once in couple of weeks or so).

If you want to see the effect, do

echo 0 > /sys/devices/omapdss/display0/backlight/display0/brightness

To get screen back "echo 7 >...". When my screen suddenly turns black, something has written 0 there. Don't know what triggers that.