Quoting David G Paschich,

> I booted my machine today with a kernel built with -current sources
> supped earlier today (1/28), and when I ran the X server, it failed to
> come up.  It printed its normal startup messages about the config
> files and font paths, and then exited.  SuperProbe also exits without
> printing any information about video devices.

Does it give, by any chance, this message?

xf86MapVidMem: could not mmap /dev/vga (Invalid argument)

This happens to me (I posted this on the port-i386 list, since it is
an i386 problem), and 2 other people said they had this problem as well.

I vaguely remember a message on a list somewhere a while ago that mmap
now does a stricter argument checking. I think it was with MAP_FIXED
and the address not being on a page boundary. Maybe this is the
problem.. but I don't have the XFree86 sources here, so I can't tell what
it is doing. A ktrace did tell me that the EINVAL comes from mmap().

- Frank