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 11:11:26 -0800 Message-ID: <878we13tb5.fsf@deeprootsystems.com> References: <20091120162933.GC2354@mvista.com> <87my2h3v9t.fsf@deeprootsystems.com> <200911201955.44354.jpihet@mvista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pw0-f42.google.com ([209.85.160.42]:60457 "EHLO mail-pw0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752390AbZKTTLX (ORCPT ); Fri, 20 Nov 2009 14:11:23 -0500 Received: by pwi3 with SMTP id 3so2248705pwi.21 for ; Fri, 20 Nov 2009 11:11:29 -0800 (PST) In-Reply-To: <200911201955.44354.jpihet@mvista.com> (Jean Pihet's message of "Fri\, 20 Nov 2009 19\:55\:44 +0100") Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Jean Pihet Cc: Maxime Petazzoni , "Premi, Sanjeev" , "linux-omap@vger.kernel.org" Jean Pihet writes: > 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 Done. I added the following note to the 'opp control' section. OPP control via sysfs is deprecated. Please use CPUfreq interfaces for DVFS.