Upgrading acpi-support to 0.85 fixed this issue for me. My Thinkpad R51 now suspends fine with the most recent kernel 2.6.15-25-686.
-- [regression] Suspend [to-RAM and to-disk] is broken in 2.6.15-25.43 https://launchpad.net/bugs/50031 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
