58. Higher resolution on a Dell E177FPb monitor using modelines in xorg.conf on Debian Testing

Update 24 May 2013: this still works fine on the optiplex (with intel onboard graphics) but when trying it on a different machine with an external nvidia card I couldn't get it to work. There only "xrandr --output VGA-0 --scale 1.1x1.1" worked.

Original post:
I've hooked up my fancy new-ish optiplex 990 to an old Dell E177FPb monitor which I bought back in 2007. For various reasons I've also removed the nvidia quattro graphics card that the optiplex 990 came with -- the main reasons being 1) I hate displayport and _need_ vga and 2) the bios forces you to press 'any key' on each boot if you leave the card in, even though you've configured the OS to use the integrated onboard graphics.

At any rate, hooking my old screen to my dell lead to a less than overwhelming experience -- and querying the 'Displays' setting in gnome showed only two resolution options: 1024x768 and 800x600. Well, I knew for a fact that the maximum resolution should be 1280x1024.

This was a bit of a surprise given that the same xorg.conf had been used together with a fancy widescreen 1920x1080 display -- yet it would not handle a 1280x1024 display? I guess this might say more about my lack of understanding how display drivers work, but whatever.

Well, in the end it turned out to be easy to enable the missing resolution mode.

First, a minimal amount of googling told me that the max resolution was 1280x1024 at 75 Hz.
"Preset Resolution: 1280 x 1024 @ 75 Hz"

Next, using gtf I generated a Modeline line.

gtf 1280 1024 75

Modeline     "1280x1024_75.00" 138.54 1280 1368 1504 1728 1024 1025 1028 1069 -HSync +Vsync

Finally, I then edited the xorg.conf (again, see this post for the entire xorg.conf), changing

Section "Monitor"
Identifier   "Monitor0"
VendorName   "Monitor Vendor"
ModelName    "Monitor Model"
EndSection

to

Section "Monitor"
Identifier   "Monitor0"
VendorName   "Monitor Vendor"
ModelName    "Monitor Model"
Modeline     "1280x1024_75.00" 138.54 1280 1368 1504 1728 1024 1025 1028 1069 -HSync +Vsync
EndSection

Doing startx to start up gnome, followed by selecting Displays, then selecting Resolution: 1280x1024 (5:4) yielded a beautifully satisfying  user experience.

I'm not one to fiddle with xorg.conf, but this time it turned out that the fix was easy once I had figured out what to do.