From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Langsdorf Subject: Re: [PATCH 6/6 v6] cpufreq, highbank: add support for highbank cpufreq Date: Wed, 28 Nov 2012 18:24:15 -0600 Message-ID: <50B6AB2F.5080903@calxeda.com> References: <1351631056-25938-1-git-send-email-mark.langsdorf@calxeda.com> <1354046672-7392-1-git-send-email-mark.langsdorf@calxeda.com> <1354046672-7392-7-git-send-email-mark.langsdorf@calxeda.com> <20121128023240.GA28170@S2100-06.ap.freescale.net> <50B60E9C.9000405@calxeda.com> <20121128145759.GB28170@S2100-06.ap.freescale.net> <20121128151741.GC28170@S2100-06.ap.freescale.net> <20121128160115.21126.3841@nucleus> <50B6395B.806@calxeda.com> <20121128210552.21126.90710@nucleus> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20121128210552.21126.90710@nucleus> Sender: linux-pm-owner@vger.kernel.org To: Mike Turquette Cc: Shawn Guo , "linux-arm-kernel@lists.infradead.org" , "devicetree-discuss@lists.ozlabs.org" , "linux-kernel@vger.kernel.org" , "cpufreq@vger.kernel.org" , "linux-pm@vger.kernel.org" List-Id: devicetree@vger.kernel.org On 11/28/2012 03:05 PM, Mike Turquette wrote: > Quoting Mark Langsdorf (2012-11-28 08:18:35) >> On 11/28/2012 10:01 AM, Mike Turquette wrote: >>> Quoting Shawn Guo (2012-11-28 07:17:44) >>>> On Wed, Nov 28, 2012 at 10:58:02PM +0800, Shawn Guo wrote: >>>>> On Wed, Nov 28, 2012 at 07:16:12AM -0600, Mark Langsdorf wrote: >>>>>> I'd >>>>>> have to move most of the logic of hb_set_target() into >>>>>> clk_highbank.c:clk_pll_set_rate() and then add extra logic for when >>>>>> cpufreq is not enabled/loaded. >>>>> >>>>> You only need to move hb_voltage_change() into cpu clock's .set_rate() >>>>> hook with no need of checking if cpufreq is enabled or not. >>>>> >>>> Need to also check whether frequency or voltage should be changed first >>>> in .set_rate() though. >>>> >>>> Shawn >>>> >>> >>> The notifiers in the clk framework might be a better place for this than >>> just simply hacking the logic into the .set_rate callback. >> >> Unless the clk notifiers are different than the cpufreq notifiers, they >> don't handle returning error conditions very well. And given that the >> voltage change operation can fail (though it almost always succeeds on a >> retry) I need to be able to handle and detect that error condition. > > The notifier handler can handle the case where the transition fails (and > needs to be retried). > > Also you should check out the clk notifiers. I think they handle > failure decently. If a notifer returns an error code then everything > unrolls and the clk_set_rate operation aborts. Thanks for the pointer. The clk notifier calls seem to be working with cpufreq-cpu0. I did enough surgery on the code that I want to run a lot of stress tests before I resubmit. I'll try to have something for Tuesday. --Mark Langsdorf Calxeda, Inc.