Another Fedora post.
I ran into this bug in Fedora 10, and by looking at those bug reports, I was able to work around it. But I had forgotten all about that when I installed Fedora 11. So I'm writing this partly as a note for myself in case the bug still exists in Fedora 12.
The problem is that Fedora incorporates something called Kernel Mode Setting for ATI Radeon GPUs. KMS is a technology that gives the kernel more responsibility for managing the graphics hardware, rather than leaving it in the hands of the X sever. Unfortunately, there is a bug in the Radeon KMS support, at least for the Radeon Mobility X1400 chip in my Thinkpad T60. It will suspend, but the video never comes back during a resume.
The workaround is to disable KMS. This can be done by adding the nomodeset option to the kernel command line in /boot/grub/grub.conf. You'll need to reboot for this to take effect.
KMS is a worthwhile technology, if for no other reason than making the Fedora boot process much prettier. But with suspend working, I rarely have to watch the boot process, so its appearance is not a major concern for me.