If 2.6.15-23 was working, and then stopped after an upgrade of pcmcia- cs, then I suspect it's not directly the kernel's fault.
** Changed in: linux-source-2.6.15 (Ubuntu) Sourcepackagename: linux-source-2.6.15 => pcmcia-cs -- Suspend and hibernate used to work - now broken https://launchpad.net/bugs/50823 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs