Hi Rafael, A kernel bug affecting several users was opened against Ubuntu[0]. After a bisect, it was found the following commit introduced the regression: commit ac212b6980d8d5eda705864fc5a8ecddc6d6eacc Author: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Date: Fri May 3 00:26:22 2013 +0200 ACPI / processor: Use common hotplug infrastructure The regression was introduced as of v3.11-rc1. This commit doesn't revert cleanly in 3.12, and requires the revert of other commits as well. I wanted to get your feedback since you are the author. Thanks, Joe http://pad.lv/1237336 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html