Just how does xorg work, anyway?

dhave · 2007-11-07 22:28:21

I used to think I understood the basics of configuring X by editing xorg.conf. Now I'm realizing that I was under an illusion.

My machine is a Thinkpad T43 which has an internal LCD display that runs natively at 1400x1050. I often connect it to a Dell 22" flat planel monitor that likes to run at 1680x1050. The configuration I describe below works fine for both displays -- or did until the other day (see below).

I have been getting good results with only one monitor defined in my xorg.conf -- the Dell 1680x1050 external flat panel. I've also got only one screen defined, and in that section, I have defined a number of resolutions that I want to make sure my flat panel can access, along with the 1400x1050 resolution that my internal LCD uses.

I don't have a separate screen or monitor definition for my laptop's LCD, but this hasn't posed a problem, for some reason.

If I am hooked up to the flat panel, xorg knows it and configures my flat panel to display at 1680x1050. If I run xrandr while I'm hooked up to the flat panel, I get 1680x1050 listed as the default of many resolutions.

If I'm NOT hooked up to the flat panel, xorg somehow manages to figure out that my laptop is running a 1400x1050 internal screen. If I run xrandr when I'm not hooked up to the flat panel, a 1680x1050 resolution doesn't even appear in the list. Also, the modes listed by xrandr are not the ones that I have defined in my screen section of xorg.conf.

Obviously a lot of this screen definition stuff is going on automatically, for which I'm probably grateful, except that xorg.conf has given me the illusion that I was exercising some control over it.

The problem surfacing now is that I'm having some glitches with the latest xorg-server updates, and I can't get my flatpanel to display at its full 1680x1050. If I was really controling things with xorg.conf, then I could manipulate values there. However, since everything seems to be in fact driven by an automatic override, I'm at a loss to try to troubleshoot things. For the time being, I've rolled back to older xorg-server packages, but I'd rather understand what's going on.

Maybe I've posted in the wrong forum, so if a nice mod will move this post to the right place, I'd appreciate it.

Thanks for any help anyone can offer.

dunc · 2007-11-07 23:02:54

Sounds like you've been hit by the same problems with the recent X update as a lot of us, to differing extents (it completely killed my system). Take a look at some of the other threads on the subject.

I like your way of putting it, though...

Obviously a lot of this screen definition stuff is going on automatically, for which I'm probably grateful, except that xorg.conf has given me the illusion that I was exercising some control over it.

I know exactly how you feel.

Arch Linux

#1 2007-11-07 22:28:21

Just how does xorg work, anyway?

#2 2007-11-07 23:02:54

Re: Just how does xorg work, anyway?

Board footer