I recently took a peak at the Ubuntu-X Team's page on the Ubuntu Wiki. I've been told that Jaunty handles XConfig differently than Intrepid or any of the other releases. Unfortunately, I'm an X novice and so can't see any discernible difference between X now and X then. xorg.conf seems to remain the central setup, and it doesn't seem that there are any new programming parameters for it. The greatest change seems to be the new "automagical" behaviors that ship with Jaunty.
One of the greatest achievements made with X seems to be "input-hotplug," which should automatically configure new devices. If this doesn't work out, though, "xinput list" seems to be the fastest output for X device issues. The Ubuntu-X team describes this particular process like this:
"Historically, X probes input devices on X startup, so devices attached subsequently may not function. To overcome this in situations like a laptop with external mouse, the kernel emulates a PS/2 mouse at /dev/input/mice (or /dev/psaux) with events coming from ANY mouse connected to the system. This mostly works, but doesn't handle multi-protocol situations perfectly (other protocols can be translated, but some events can be lost in the process)... Without input-hotplug, all input devices need to be configured in xorg.conf, thus adding a new device or reconfiguring a device would require an X restart."
Not everything has been automated as of yet, though. "Virtual" framebuffers, such as dual-screen output, need to be defined manually in xorg.conf (which, I will attest, is a veritable impossibility for casual home users).
DontZap and Sticky Keys
In addition, die-hard X users will notice that CTRL-ALT-BACKSPACE does nothing now (Wha?!). The Ubuntu-X team describes their reasoning for this revision:
"The DontZap option in the /etc/X11/xorg.conf file enables or disables the CTRL-ALT-BACKSPACE shortcut to restart the X-server. In previous Ubuntu releases, this shortcut was enabled by default, however this will change starting with 9.04 "Jaunty", as a number of users have complained about accidentally restarting their X-Server."
The fix for this is simple, though.
Sticky Keys is part of the impetus for this revision. Holding down the shift-key for 8 seconds enables Sticky Keys, making the CTRL key "sticky," for the purposes of keyboard shortcuts. Apparently, a sizable number of people enable this option, then accidentally restart their X-Servers.
There's probably more to the new X configuration than I've flushed out. More to follow.