From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755137AbWKMPcb (ORCPT ); Mon, 13 Nov 2006 10:32:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755138AbWKMPcb (ORCPT ); Mon, 13 Nov 2006 10:32:31 -0500 Received: from srv5.dvmed.net ([207.36.208.214]:138 "EHLO mail.dvmed.net") by vger.kernel.org with ESMTP id S1755137AbWKMPcb (ORCPT ); Mon, 13 Nov 2006 10:32:31 -0500 Message-ID: <45589008.1080001@garzik.org> Date: Mon, 13 Nov 2006 10:32:24 -0500 From: Jeff Garzik User-Agent: Thunderbird 1.5.0.8 (X11/20061107) MIME-Version: 1.0 To: Pavel Machek CC: John Fremlin , kernel list , htejun@gmail.com, jim.kardach@intel.com, ak@suse.de Subject: Re: AHCI power saving (was Re: Ten hours on X60s) References: <87k639u55l.fsf-genuine-vii@john.fremlin.org> <20061009215221.GC30702@elf.ucw.cz> <87ods6loe8.fsf-genuine-vii@john.fremlin.org> <20061025070920.GG5851@elf.ucw.cz> <87y7r3xlif.fsf-genuine-vii@john.fremlin.org> <20061026204655.GA1767@elf.ucw.cz> <87slgv6ccz.fsf-genuine-vii@john.fremlin.org> <20061112183614.GA5081@ucw.cz> <87hcx3adcd.fsf-genuine-vii@john.fremlin.org> <20061113142219.GA2703@elf.ucw.cz> In-Reply-To: <20061113142219.GA2703@elf.ucw.cz> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -4.3 (----) X-Spam-Report: SpamAssassin version 3.1.7 on srv5.dvmed.net summary: Content analysis details: (-4.3 points, 5.0 required) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Pavel Machek wrote: > --- a/drivers/ata/ahci.c > +++ b/drivers/ata/ahci.c > @@ -148,6 +148,8 @@ enum { > PORT_IRQ_PIOS_FIS | PORT_IRQ_D2H_REG_FIS, > > /* PORT_CMD bits */ > + PORT_CMD_ALPE = (1 << 27), /* Aggressive Link Power Management Enable */ > + PORT_CMD_ASP = (1 << 26), /* Aggressive entrance to Slumber or Partial power management states */ > PORT_CMD_ATAPI = (1 << 24), /* Device is ATAPI */ > PORT_CMD_LIST_ON = (1 << 15), /* cmd list DMA engine running */ > PORT_CMD_FIS_ON = (1 << 14), /* FIS DMA engine running */ > @@ -486,7 +488,7 @@ static void ahci_power_up(void __iomem * > } > > /* wake up link */ > - writel(cmd | PORT_CMD_ICC_ACTIVE, port_mmio + PORT_CMD); > + writel(cmd | PORT_CMD_ICC_ACTIVE | PORT_CMD_ALPE | PORT_CMD_ASP, port_mmio + PORT_CMD); Therein lies a key problem. Turning on all of AHCI's aggressive power management features DOES save a lot of power. But at the same time, it shortens the life of your hard drive, particularly hard drives that are really PATA, but have a PATA<->SATA bridge glued on the drive to enable connection to SATA controllers. Jeff