[TriLUG] Widescreen display

Alan Porter porter at trilug.org
Wed Jan 24 13:15:47 EST 2007


> I just got a nice widescreen monitor and would like to get the 
> according resolution on it. However, even though (I think) I changed 
> xorg.conf to match the monitor, I'm still getting a "stretched" 
> 1280x1024 instead of the 1440x900 of which the monitor is capable. Any 
> advice?

My wife has a Dell laptop that has the i810 video controller. It had a 
similar problem. I'm not sure if this is the same issue, but it's worth 
a try.

After doing a bit of poking around, I found out that her problem was a 
video BIOS problem. The video BIOS has a list of screen resolutions that 
it will support. When X starts, it probes the video BIOS to see whether 
the desired screen resolution should work. It turns out the the i810 
will support several widescreen resolutions that are not listed in the 
video BIOS. The crazy part is that the laptop's video BIOS did not have 
the LCD's native resolution in its list of supported modes!!

As we might expect, some enterprising Linux hacker has made a work-around.

To fix the laptop video problem, I installed a tool called 
"855resolution" (http://perso.orange.fr/apoirier/). First, I ran 
"855resolution -l" to list all of the video modes. I picked a video mode 
that I thought I would never use (5c).

When the system starts up (before X starts), I run "855resolution 5c 
1400 1050". The first argument is the video mode from above. The mode 
number itself is arbitrary. This tool pokes the desired resolution (in 
my case, 1400x1050) into the shadow RAM of the video BIOS to replace the 
given video mode. Since the tool only modifies the RAM copy of the video 
BIOS, the change has to be made every time the machine is booted. It 
also means that it's not permanently modifying anything.

Like magic, once X starts, it probes and gets the match that I'm looking 
for, and X then uses my desired resolution setting.

Weird, huh?

I'd be really interested in hearing if this same fix cures your 
widescreen problem.

Alan





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