From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roger Quadros Subject: Re: [RFC] MMC: Proposals on reworking clock and power management Date: Fri, 29 Oct 2010 13:47:59 +0300 Message-ID: <4CCAA65F.2050905@nokia.com> References: <2A3DCF3DA181AD40BDE86A3150B27B6B0356A579AF@dbde02.ent.ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mgw-sa02.nokia.com ([147.243.1.48]:34868 "EHLO mgw-sa02.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753326Ab0J2Kqu (ORCPT ); Fri, 29 Oct 2010 06:46:50 -0400 In-Reply-To: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: ext Ohad Ben-Cohen Cc: Kishore Kadiyala , Nicolas Pitre , "Ghorai, Sukumar" , Chris Ball , Linus Walleij , Adrian Hunter , "linux-mmc@vger.kernel.org" , "Kadiyala, Kishore" , "Chikkature Rajashekar, Madhusudhan" , "S, Venkatraman" On 10/28/2010 11:51 PM, ext Ohad Ben-Cohen wrote: > On Thu, Oct 28, 2010 at 6:40 PM, Kishore Kadiyala > wrote: >> On Thu, Oct 28, 2010 at 9:43 PM, Nicolas Pitre wrote: >>> This is not clear that this is something that the core can effectively >>> help with. Opportunistic power saving at the host controller level is >>> pretty much hardware dependent and may wildly vary in capabilities... >>> and bugs. So in this later case I think the driver for the host >>> controller is the best place to just set up a timer and gate the clock >>> after a certain period of inactivity for example. > > makes sense, thanks. just to be sure, we're talking about controller clock and not card clock. right? > >> Agree, >> So briefly, calling pm_runtime_put_sync using a activity based timer >> in the host Controller >> driver will gate the clock to the controller . > > Just make sure you call pm_suspend_ignore_children(), because you want > to be able to gate that clock even when the card is still active Let's be specific when we say clock. Which clock? -- regards, -roger