So, I just bought a 32" Panasonic LCD (1080p) and have decided to use that as my main monitor. Unfortunately, when I hooked it up to my computer, I had under-scan with both Windows 7 x64 and Ubuntu Karmic x64 (using a Radeon HD 4870 1GB). In Windows, there was a simple slider in the Catalyst Control Center to fix the under-scan issue. Unfortunately, the same option wasn't available with the Linux counterpart. I searched online for some answers, but all the ones I found seemed outdated, or gave me errors. Using the Aticonfig help command, I figured out how to fix the under-scan in Linux.
Step 1, identify your DISPLAYTYPE:
The choices are:
For my LCD, the correct option was "tmds1". The way you decide which one you have is by executing the following command:
crt1, lvds, tv, cv, tmds1, crt2,
tmds2, tmds2i, dfp1, dfp2, dfp3, dfp4, dfp5, dfp6 .
where DISPLAYTYPE is one of the above choices. If it is the correct choice, you'll receive a bunch of information that probably looks like the resolution numbers you are shooting for. You know you chose the wrong choice if you get an output like:
Also, you can try "Xrandr -q" and see which option is listed as connected.
Query information of sizeX attribute failed, may not supported by monitor crt1.
Step 2, custom fit your screen parameters:
Once you've figured out which is your DISPLAYTYPE, now you need to try and get positions and sizes that correspond to the actual pixels on your monitor. Unfortunately, every monitor is different, so you'll just have to play guess and check. Start by setting your position. For me, I found these two commands to put my image at the top left of the screen (filling in DISPLAYTYPE with the parameter you found):
Once you have gotten your image in the top left corner, now it is time to set your length and width of the image. My monitor displays at 1920x1080, but as I am starting an x position of 50, then the size value is going to be considerably less than 1920 (and likewise for the height). These commands did it for me (filling in DISPLAYTYPE with the parameter you found):
Step 3, making your changes permanent:
At this point, you should have custom tailored the displayed image to fill up your monitor using the afore mentioned commands. Now, if you reboot the computer, the under-scan will return, so we need to make these changes permanent. Open gedit (type gedit on command line or open it from the Applications->Accessories->Gedit). On the first line, enter:
Then, make an empty line after, and then paste the four aticonfig commands you used earlier (starting with positions, then with sizes). Save the file as "ati-overscan" (without quotes). For example, my file looks like this:
Now, go to System->Preferences->Startup Applications. Click on Add, and browse to where ever you saved that script. Give it a name and a description if you'd like, and click OK. Now you're done!
Don't try any of these Aticonfig commands while you have some 3d application running. Just do it with a terminal running on your desktop and no other applications open. That will reduce the likely hood that the fglrx drivers won't crash the system.
Note: ATI, please just add a slider in CCC like you do in Windows. I cannot imagine it being that difficult to add, given that all this already works. I was really hoping Catalyst 10.2 would include such a slider, but alas...