I just found out the same after two hours of chasing logs and reading the platform-driver-x86 list :D
In short: I can confirm the bug on Maverick and Natty.
As it has been mentioned, "acer_wmi" should be blacklisted and "ideapad_acpi" should be added to /etc/modules instead. Beware: "ideapad_acpi" is a fairly recent module (August), it is included in Natty's -36 kernel but I don't know about maverick's -35!
I just found out the same after two hours of chasing logs and reading the platform-driver-x86 list :D
In short: I can confirm the bug on Maverick and Natty.
As it has been mentioned, "acer_wmi" should be blacklisted and "ideapad_acpi" should be added to /etc/modules instead. Beware: "ideapad_acpi" is a fairly recent module (August), it is included in Natty's -36 kernel but I don't know about maverick's -35!