I have an AMD Radeon 6850 in my set up which is connected to my monitor via an hdmi cable. After installing the latest fglrx drivers, version 12.6, I need to drag the overscan slider all the way to the right to make the desktop properly fit my monitor. But now after every reboot the overscan image is very small and there is about a 2 inch large border around my display. When I open Catalyst Control Center the overscan slider is still as far to the right as possible, but when I slide it all the way to the left and then to the right again it fits my screen perfectly. How to I stop this small inconvenience?

  • I have exactly the same issue. So annoying as I was using this on my HTPC now requires a mouse for every boot -.- Also the latest 12.6 fglrx from AMD site with an AMD Radeon HD 5450. Ubuntu 12.04 minimal + gnome3-core.
    – Vort3x
    Aug 6, 2012 at 4:59
  • Did you open catalyst with admin permissions? I have 2 options: one as a normal user and one as admin. You must use the 2nd one.
    – Rinzwind
    Aug 10, 2012 at 9:30

2 Answers 2


Open a terminal with Ctrl+Alt+T and enter the following:

sudo amdconfig --set-pcs-val=MCIL,DigitalHDTVDefaultUnderscan,0

Then reboot.

  • PCS commands can only be performed by root
    – Rinzwind
    Aug 10, 2012 at 9:31
  • You are. My hero.
    – Vort3x
    Aug 16, 2012 at 18:40
  • If using the fglrx-driver package: sudo aticonfig --set-pcs-val=MCIL,DigitalHDTVDefaultUnderscan,0
    – AWippler
    Jun 21, 2014 at 16:04

I used @user188647 's answer as inspiration, but the command wasn't working.

So I edited /etc/ati/amdpcsdb, and in the AMDPCSROOT/SYSTEM/MCIL section, added:


Then I shut down the X server, started it up again and voila! No underscan.

Inspired by: https://github.com/OpenELEC/OpenELEC.tv/issues/1636

  • fixed ot for me, be carfeul so you dont enter anything wron here thought :)
    – Kristoffer
    Sep 6, 2013 at 19:38

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