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 20:19:00 +0100 Message-ID: <200911202019.00162.jpihet@mvista.com> References: <200911201955.44354.jpihet@mvista.com> <878we13tb5.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]:45618 "HELO gateway-1237.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with SMTP id S1755261AbZKTTTK (ORCPT ); Fri, 20 Nov 2009 14:19:10 -0500 In-Reply-To: <878we13tb5.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" On Friday 20 November 2009 20:11:26 Kevin Hilman wrote: > 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. Thanks! Jean