> The rule is that you don't break userspace. It's a very simple rule to understand.
Well, I don't know how general that rule is, because kernel 2.6.36 ripped out an important set of /proc/acpi entries that are still used on older Gnome releases (eg. CentOS-5).
A separate project, named ELRepo, provides backported kernel modules, but also the current mainline kernel built specifically for CentOS-5. Which is great for testing/running the latest kernel with a stable and trusted distribution. Since 2.6.36, not anymore, as my laptop couldn't provide proper ACPI information, and as such couldn't suspend/hibernate before running out of power :-(
More information about this, and other breakage is available from: