From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH] ahci: Turn off DMA engines when there's no device attached Date: Sun, 28 Mar 2010 00:39:04 -0400 Message-ID: <4BAEDD68.60008@pobox.com> References: <1268253150-24050-1-git-send-email-mjg@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-gx0-f217.google.com ([209.85.217.217]:44882 "EHLO mail-gx0-f217.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751775Ab0C1EjJ (ORCPT ); Sun, 28 Mar 2010 00:39:09 -0400 Received: by gxk9 with SMTP id 9so801464gxk.8 for ; Sat, 27 Mar 2010 21:39:08 -0700 (PDT) In-Reply-To: <1268253150-24050-1-git-send-email-mjg@redhat.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Matthew Garrett Cc: linux-ide@vger.kernel.org, Kristen Carlson Accardi On 03/10/2010 03:32 PM, Matthew Garrett wrote: > According to section 10.3.1 of the AHCI spec, PxCMD.ST must not be set > unless there's a device attached. Following this saves us a measurable > quantity of power and does not impair hotplug support. Based on a patch > by Kristen Carlson Accardi. > > Signed-off-by: Matthew Garrett > Cc: Kristen Carlson Accardi > --- > drivers/ata/ahci.c | 19 +++++++++++++++++++ > 1 files changed, 19 insertions(+), 0 deletions(-) applied manually to libata-dev.git#upstream, due to large code movements in creation of new libahci kernel module