Some progress with Catalyst 12.11 beta 8 drivers
As reported by a few already the beta 8 drivers SIGSEGV steam.
I ran steam with gdb to see if I could skip past the errant code and get it to work.
I noticed the crash happened in a X11 function called 'XQueryExtension' because a returned parameter, which should be a function pointer, has the value 31 and causes a page zero seg fault.
Earlier in the stack trace I see the driver is calling ADL_ApplicationProfiles_System_Reload()
Which, I tested and saw is not called by the previous beta driver.
So, I set a breakpoint at the function and just used gdb's return command so none of that code ran.
And that worked. The steam window popped up, logged in and then told me I wasn't in the beta. Ya boo :)
So, those with gdb knowledge and an ati card might have some luck running TF2, if you do the same, set a breakpoint on this function and when it's hit, just do 'return'. Of course, you might need to detatch GDB at some point, otherwise any performance gain may well be lost.
But presumably this shows that Application profiles are the issue. Perhaps we need one for this new driver and they didn't include it? Or perhaps we could copy something from our windows installs of the driver to stop the segfault happening?
I'm going to try to get TF2 running now.