Forcing screen resolution when monitor type not detected

[ChuckZ]

OS: Fedora 12
Video card: ATI Radeon 9200 series
Monitor: ViewSonic 19"

I installed Fedora 12 configured Gnome automatically. Generally default settings. My monitor was connected directly to the video card and all was good. My video card was detected and my monitor was detected as ViewSonic Corporation 19" and I can set the screen resolution to 1280x1024. I had no xorg.conf file, as it seems that Fedora 12 does a great job of PnP to just set everything up.

Now I go and complicate things by hooking up my monitor through a KVM switch. All of a sudden my monitor is "Unknown" and the best resolution I can achieve is 800x600.

Sure, I could go and reconnect without the KVM, but I want to be able use it.
Is it possible to edit xorg.conf to tell it "Trust me, just use 1280x1024 at 60Hz even though you can't figure out what the monitor is"?

I tried a number of the posted suggestions to generate xorg.conf files but none of them get me what I need. A simple sample file listing that does the minimum is greatly appreciated (I can experiment from there once I get a basic setup working).

And can someone explain if it is X or the ATI driver that is getting confused by the unknown monitor type. It helps to know what is actually going on in addition to a fix (so I can figure it out myself in the future). Thanks!

[devils casper]

Hi and Welcome !

Did you install ATI Proprietary driver?
Post the output of this

su -c /sbin/lspci | grep -i vga

Post the contents of /etc/X11/xorg.conf file here.

[ChuckZ]

I had to reinstall Fedora 12 (my earlier messing with xorg.conf left me in a state that Gnome wouldn't start). I reinstalled with the KVM attached this time.

Here is the result of the command suggested (run as root).

/sbin/lspci | grep -i vga
01:00.0 VGA compatible controller: ATI Technologies Inc RV280 [Radeon 9200 PRO] (rev 01)

I did install the ATI driver. I was given two choices on the ATI site:
XFree86 4.3 Drivers
X.Org 6.8 Drivers

I chose the X.Org 6.8 Drivers. It appeared to install (and required some dependencies). I do not know what to check to verify that it actually installed correctly.

Right now, there is no xorg.conf file (given my fresh re-install and driver install).
When I go to set the display settings, I still see Unknown monitor and can only choose low resolutions as before.
I have not restarted X yet, but will reboot and see if anything changes.

[bennis]

Hello ChuckZ,

I also had some trouble getting the resolution I wanted, though not with the KVM switch complication. To get an xorg.conf file I ran, as root : Xorg --configure
and an xorg.conf was placed in root's home: /root. I then added the modeline I wanted in the Screen section so that it was included in a subsection like this:

SubSection "Display"
Viewport 0 0
Depth 24
Modes "1024x768"
EndSubSection

Then it worked for me. I think I needed to run Xorg --configure without X running to get the xorg.conf. The KVM complication I have had in the past has been with the hardware of the KVM itself, so I abandonned it. I hope this is useful to you.