Introduced in Ubuntu 7.10 was a feature known as BulletProofX, which provides a fail-safe mode that is by default used when the X server fails to properly initialize. In this original implementation, it would default back to using the VESA display driver with 256 colors and then proceed to run the displayconfig-gtk utility. While this is nice for the end-user as it keeps them from touching a terminal to debug an X server problem, for experienced users it inhibits them from easily debugging the problem. This Canonical implementation also had frustrated other users. However, with the forthcoming Ubuntu 8.10 release, it has received some much-needed improvements while making BulletProofX more simple.
On second though, can't you ctrl-alt-F1 switch to a VT and go on from there?
Anyway, this looks like a good enhancement. Just prepared my liveusb, so I'll be testing shortly. Up to now 8.10 is looking great!
Edit: Ok, typing from my liveusb now and I actually take what aI said back. The current approach is quite zen: people who know how to debug from the commandline already know how to switch there. People who don't, will be presented with sensible choices that allow them to keep using the system (even at reduced functionality).
I still remember the first time X crashed on me. No idea what to do (wtf is xorg.conf?), searching the internet through lynx. Ugh! Newbies have it easy nowadays :P
I just tested it, I tried to install fglrx on 8-10 a6, but all logs it shows is with the vesa failsave config. Usually it would be more usefull when the /var/log/Xorg.0.log.old would be shown. Of course you can change the vt and look there too, but nobody needs the current vesa log file as the gui is already shown with vesa...
@colo, actually I did include a "drop to root prompt" option in the original implementation. Problem was that dropping to a root session without prompting for a password resulted in a security hole. For the life of me I couldn't figure out a good robust and reliable way to prompt for password. In the end I figured anyone who could make use of a root prompt probably also would know to vt switch, and left it at that.