Ctrl+Alt+F1 doesn't switch to text console on potato

[Eric Hanchrow <offby1@blarg.net>]

I have both slink and potato installed on my machine, and have set up X
similarly on both:  xserver-svga (Version: 3.3.5-1 on potato; Version:
3.3.2.3a-11 on slink).  On slink, while running X, when I type
Ctrl+Alt+F1, the screen switches into text mode and shows me virtual
terminal 1, so I could log in again, or do whatever.  However, on
potato, Ctrl+Alt+F1 does nothing.

I wouldn't be surprised if this were due to some configuration
difference between the machines, but I don't know where to look to find
out (I've looked at XF86Config, the XFree86 HOWTO, the
XWindow-User-HOWTO).  Might this be a bug?  Or can anyone suggest which
configuration files control this behavior?

Thanks