From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: VDD1 voltage after resume from idle Date: Fri, 20 Nov 2009 10:29:02 -0800 Message-ID: <87my2h3v9t.fsf@deeprootsystems.com> References: <20091120162933.GC2354@mvista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-px0-f204.google.com ([209.85.216.204]:53819 "EHLO mail-px0-f204.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751652AbZKTS26 (ORCPT ); Fri, 20 Nov 2009 13:28:58 -0500 Received: by pxi42 with SMTP id 42so1943720pxi.5 for ; Fri, 20 Nov 2009 10:29:04 -0800 (PST) In-Reply-To: <20091120162933.GC2354@mvista.com> (Maxime Petazzoni's message of "Fri\, 20 Nov 2009 17\:29\:33 +0100") Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Maxime Petazzoni Cc: "Premi, Sanjeev" , "linux-omap@vger.kernel.org" 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. Kevin