From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759094Ab0E1D5u (ORCPT ); Thu, 27 May 2010 23:57:50 -0400 Received: from vms173011pub.verizon.net ([206.46.173.11]:56402 "EHLO vms173011pub.verizon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755470Ab0E1D5t (ORCPT ); Thu, 27 May 2010 23:57:49 -0400 Date: Thu, 27 May 2010 23:57:42 -0400 (EDT) From: Len Brown X-X-Sender: lenb@localhost.localdomain To: Andrew Morton Cc: x86@kernel.org, linux-pm@lists.linux-foundation.org, Linux Kernel Mailing List Subject: Re: [PATCH 8/8] intel_idle: create a native cpuidle driver for select intel processors In-reply-to: <20100526204426.fd2be7e0.akpm@linux-foundation.org> Message-id: References: <1274928151-30919-1-git-send-email-lenb@kernel.org> <198450ec1600d9a7f55270dd4d44d6b55bc5b184.1274926772.git.len.brown@intel.com> <20100526204426.fd2be7e0.akpm@linux-foundation.org> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-version: 1.0 Content-type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > ... What happens when an additional CPU is brought online? > It melts? ;) With the current driver, processors hot-added after modprobe will use C1 only, and not use deeper C-states. Taking online processors offline and bringing them back online (like we do during suspend) works fine. > > + dev->cpu = i; > > + if (cpuidle_register_device(dev)) { > > + pr_debug(PREFIX "cpuidle_register_device %d failed!\n", i); > > + free_percpu(intel_idle_cpuidle_devices); > > + return -EIO; > > Should this unregister all the thus-far-registered devices? yes, that was a bug! thanks, Len Brown, Intel Open Source Technology Center