From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964854Ab1KJPhR (ORCPT ); Thu, 10 Nov 2011 10:37:17 -0500 Received: from mail-gx0-f174.google.com ([209.85.161.174]:39481 "EHLO mail-gx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757707Ab1KJPhO (ORCPT ); Thu, 10 Nov 2011 10:37:14 -0500 Date: Thu, 10 Nov 2011 07:37:07 -0800 From: Tejun Heo To: Alan Stern Cc: Lin Ming , linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org, linux-pm@vger.kernel.org, Jeff Garzik , "Rafael J. Wysocki" , James Bottomley , Huang Ying , Zhang Rui Subject: Re: [PATCH v2 0/4] ata port runtime power management support Message-ID: <20111110153707.GE27258@google.com> References: <1320906166-15459-1-git-send-email-ming.m.lin@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 10, 2011 at 10:30:53AM -0500, Alan Stern wrote: > Currently, disks will not be runtime-suspended unless (1) the user > requests it by setting the appropriate power/control attribute, and (2) > the device file is closed (in particular, the disk has no mounted > filesystems or swap partitions). I don't imagine this combination of > events is very common for disks using libata. Empty ports are pretty common and pm should be able to put the unoccupied ports and the containing pci device into sleep state which can save some power. Would be nice to have some numbers tho. But either way, if this doesn't break anything, I don't see any reason to object to it - the hierarchy reorg is more of logical cleanup and runtime pm is trivial afterwards. Thanks. -- tejun