>AFAIK, most graphics cards manufactured so far need such timing
>information for mode switch. It's not chip dependant. If it were,
>for what does XFree86 provide common mode lines in XF86Config file? 

	i'm no expert in various VGA cards these days, but isn't it better
	to let BIOS handle it?  i.e. call VGA BIOS for initialization and
	let it initialize the parameter, instead of cooking up parameters.
	kvm86.c looks promising for this...(assuming VGA BIOS gives you
	enough functionality)

itojun