From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Pihet Subject: Re: VDD1 voltage after resume from idle Date: Fri, 20 Nov 2009 19:55:44 +0100 Message-ID: <200911201955.44354.jpihet@mvista.com> References: <20091120162933.GC2354@mvista.com> <87my2h3v9t.fsf@deeprootsystems.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from hu47.mvista.com ([206.112.117.47]:44064 "HELO gateway-1237.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with SMTP id S1755000AbZKTSzy (ORCPT ); Fri, 20 Nov 2009 13:55:54 -0500 In-Reply-To: <87my2h3v9t.fsf@deeprootsystems.com> Content-Disposition: inline Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Kevin Hilman Cc: Maxime Petazzoni , "Premi, Sanjeev" , "linux-omap@vger.kernel.org" Hi Kevin, On Friday 20 November 2009 19:29:02 Kevin Hilman wrote: > Maxime Petazzoni writes: > > Hi, > > > > * Premi, Sanjeev [2009-11-20 21:17:04]: > >> I am facing a strange problem on OMAP3EVM after resuming from idle. > >> When using OPP5, the VDD1 voltage ramps to 1.35V. > >> > >> However, when i go thru the idle/wakeup cycle, the voltage never > >> ramps back to 1.35V but stays at 1.20V. > > > > I'm seeing some interesting behavior with the OPP values here, too, with > > suspend/resume. I'm using SRF based PM and CPUFREQ. Here's what happens: > > > > When changing the CPU frequency through the scaling_setfreq knob of > > CPUFREQ, the vdd{1,2}_opp values are updated accordingly. After a > > suspend/resume cycles, the OPPs return to their pre-suspend values, all > > is fine. > > > > But when changing the OPP values by hand through the vdd{1,2}_opp knobs, > > the CPU frequency is changed accordingly, which is expected. But after a > > suspend/resume cycle, the OPP values return to the value CPUFREQ set > > them to (which may be different than the default OPP values of 3). > > > > Is this the normal behavior? Is cpufreq authoritative on the OPP values > > on resume? Or should it follow whatever value was manually set before > > suspending? > > FWIW, the vdd*_opp sysfs hooks were for initial debug/dev and should > be considered experimental (a.k.a broken.) They will disappear from > the PM branch shortly. > > CPUfreq should be the only interface used for DVFS. Could the PM page on elinux.org be updated with that info? I am proposing to change it before you ask me ;p > > Kevin Thanks, Jean > -- > To unsubscribe from this list: send the line "unsubscribe linux-omap" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html