My laptop is relatively old (2008) Acer 5520G with video Mobility Radeon HD 2400 XT on board.
The problem is related to radeon driver. I don’t know should it be filed as a bug report to freedesktop.org. In 11.4 as well as in 12.1 I experience the problem with suspend/resume. Laptop suspends, but when I try to resume it, I see only a blank screen with a mouse cursor. This is true for KDE, Gnome, opensuse 11.4, 12.1, Fedora 16. In opensuse 11.2 clicking on suspend locked the screen and the laptop did not suspend. My experiments show that it is related to problems with KMS and radeon driver. In tty1 I see scrolling messages
[drm:radeon_ib_schedule] ERROR radeon: couldn’t schedule IB(0)
[drm:radeon_ib_schedule] ERROR radeon: couldn’t schedule IB(1)
…
[drm:radeon_ib_schedule] ERROR radeon: couldn’t schedule IB(15).
In OS 11.4 there were error messages too. This led to artifacts in KDE after reboot: horizontal lines on plasma panels, menus, etc. Ctrl+Alt+Backspace and reboot helped me to remove those artifacts almost every time. Even in init 1 when I use s2ram and try resuming the result is the same:
[drm:radeon_ib_schedule] ERROR radeon: couldn’t schedule IB(0)… (OS 12.1).
I tried to install kernel 3.1.8. The bug is not fixed there. In /var/log/Xorg.0.log there are errors:
54.726] (EE) Failed to load module “fglrx” (module does not exist, 0)
54.778] (EE) FATAL: RadeonHD presently does not work with kernel modesetting (KMS).