[BRM]

Originally Posted by ts1

It's a pretty lightweight shader. Something wrong with your GPU drivers/setup. I tried it on Linux and it works fine with proprietary nVidia drivers, but with nouveau it's also not usable, very slow.
There is parameter to control sharpening strength.

I know, I get similar results with the 2-pass shader.
As for my setup, it's radeon-git, xorg.conf and xorg.conf.d/20-radeon.conf are as follows: http://pastebin.com/raw/aE3e21Bn

  Section "Device"
          Identifier "radeonVGA"
                      Driver "radeon"
                      Option "AccelMethod" "Glamor" # See compatibility on features page
                      Option "DRI3" "on" # Compatibility not very well documented, remove it if it fails
                      Option "EnablePageFlip" "On"
  EndSection