Forcing the vesa driver, how?

[gene heskett]

Greetings all;

I have now installed ubuntu-10.04 LTS on my old box that runs my milling 
machine, and its a disaster in terms of speed compared to 6.06.

One thing that is a given is that I must use the vesa driver because all 
the others, including the radeon driver from the 10.04 install, do not seem 
to share interrupts well, or some such, causing 'unexpected realtime 
delays' of as much as 2 milliseconds, intolerable in a system driving 
stepper motors step by step.

This application uses the RTAI facilities to run the machine in real time, 
and that works.  However my screen updates are at about 1.5 second 
intervals, and the position shown for the machines cutting tool is often as 
much as 5 seconds behind the machine.

The vesa driver (its an ATI-9200SE card) will actually be considerably 
faster in this application.  Its 'realtime delays' are about 1/5th those of 
the radeon driver.

So, since there is not an /etc/X11/xorg.conf file now, how do I force x to 
use the vesa driver at its optimum settings?

Thanks.

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Luck, that's when preparation and opportunity meet.
		-- P.E. Trudeau

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Bus error -- driver executed.