From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH] libata: Add ALPM power state accounting to the AHCI driver Date: Mon, 16 Nov 2009 03:26:19 +0900 Message-ID: <4B0047CB.5080509@kernel.org> References: <20091113192429.4dfc9c39@infradead.org> <4AFFB65F.3020201@kernel.org> <4AFFBB75.7050601@pobox.com> <20091115094630.1785b5ca@infradead.org> <4B004328.8060807@kernel.org> <20091115102334.1396eea6@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from hera.kernel.org ([140.211.167.34]:42491 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753463AbZKOS0Z (ORCPT ); Sun, 15 Nov 2009 13:26:25 -0500 In-Reply-To: <20091115102334.1396eea6@infradead.org> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Arjan van de Ven Cc: Jeff Garzik , linux-ide@vger.kernel.org, akpm@linux-foundation.org Arjan van de Ven wrote: > On Mon, 16 Nov 2009 03:06:32 +0900 > Tejun Heo wrote: > >> There's DIPM. > > where in the code is this? In ata_dev_set_dipm()? > And just to be clear: DIPM is done by the hardware so that it needs > sampling/etc features, rather than just straightforward (free) software > accounting when you do software controller transitions ? Enabling DIPM means that the drive will be in charge of transitioning the link into powersave modes, so if sampling SStatus is necessary to determine how much time the link spends in powersave mode. Thanks. -- tejun