From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Ball Subject: Re: [RFC RESEND] sdhci-s3c: support clock enable/disable (clock-gating) Date: Thu, 30 Sep 2010 05:09:58 +0100 Message-ID: <20100930040958.GA3170@void.printf.net> References: <4C91BD5A.1040804@samsung.com> <20100929233751.GA31473@void.printf.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from void.printf.net ([89.145.121.20]:45123 "EHLO void.printf.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750894Ab0I3EKE (ORCPT ); Thu, 30 Sep 2010 00:10:04 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Nicolas Pitre Cc: Jaehoon Chung , Adrian Hunter , linux-mmc@vger.kernel.org, Kyungmin Park , matt@console-pimps.org, Andrew Morton , Marek Szyprowski , Linus WALLEIJ , Pierre Ossman , Kukjin Kim Hi, On Wed, Sep 29, 2010 at 11:42:01PM -0400, Nicolas Pitre wrote: > As I already said here: > > http://article.gmane.org/gmane.linux.ports.arm.omap/39411 > > I find those callbacks rather problematic. Currently, > mmc_host_disable() is called by the host driver (currently OMAP) and > that's wrong. Such decision cannot be made in the controller driver -- > it has to be made higher up the stack. I strongly agree. I hadn't noticed that aspect of this design until today. It looked like Linus W had a nice core-integrated clocking framework almost ready to go a year ago, but it lost out. (Something left to do was to give extra time after a request in case we're on a broken card which requires the card clock to be present during its writeback.) I'm not sure where to go from here -- advice welcome. It would perhaps be ideal if Linus W and Adrian could work together to make the current framework look more like Linus' original intent and then move omap_hsmmc to it as painlessly as possible. Of course I wouldn't expect this to happen quickly. In the meantime, I would suggest that we should not accept any more users of this framework, which would be a NACK to Jaehoon's patch (which appears to my reading not to achieve any power-saving anyway). Adrian, I'm sorry that I'm suggesting reverting -- or at least strongly modifying -- a framework after it's already shipped in a release; if you think this is unreasonable, I'll consider your argument carefully. Thanks, -- Chris Ball One Laptop Per Child