From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lukasz Majewski Subject: Re: [PATCH v2 2/2] Documentation: devicetree: Add boost-frequency binding to list boost mode frequency Date: Mon, 10 Feb 2014 08:38:36 +0100 Message-ID: <20140210083836.44b519bf@amdc2363> References: <1391786342-11812-1-git-send-email-thomas.ab@samsung.com> <1391786342-11812-3-git-send-email-thomas.ab@samsung.com> <52F50698.4060305@arm.com> <52F509BD.70903@arm.com> <52F51888.5010608@arm.com> <52F51FCD.5000009@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-reply-to: Sender: linux-pm-owner@vger.kernel.org To: Thomas Abraham , Sudeep Holla Cc: Nishanth Menon , "linux-pm@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "rjw@rjwysocki.net" , "linux-samsung-soc@vger.kernel.org" , "kgene.kim@samsung.com" , "t.figa@samsung.com" , "viresh.kumar@linaro.org" , "thomas.ab@samsung.com" , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala List-Id: linux-samsung-soc@vger.kernel.org Hi Thomas, Sudeep, > On Fri, Feb 7, 2014 at 11:32 PM, Sudeep Holla > wrote: > > On 07/02/14 17:37, Nishanth Menon wrote: > >> On Fri, Feb 7, 2014 at 11:31 AM, Sudeep Holla > >> wrote: > > > > [...] > > > >>> Yes I think its counter-intuitive as it's visible to the > >>> userspace(list of frequencies and the boost parameters are > >>> exposed through sysfs) > >> > >> That will be a different problem -> as currently every single > >> frequency in the cpufreq list has ability to be marked as boost > >> frequency - if userspace does not maintain that, then, IMHO, fix > >> the userspace :D > >> > > > > /sys/devices/system/cpu/cpu*/cpufreq/scaling_available_frequencies > > gives the list of frequencies based on the state of the boost > > feature at anytime. > > The list of frequencies in > /sys/devices/system/cpu/cpu*/cpufreq/scaling_available_frequencies > does not change based in the state of the boost feature (enabled or > disabled). But the scaling_max_frequency and scaling_min_frequency are > updated based on the set of available + boost frequencies available. With boost intended behavior is as follow: /sys/devices/system/cpu/cpu*/cpufreq/scaling_available_frequencies [1] shows the non boost frequencies no matter if boost is enabled or not. Those are the "normal" frequencies. When boost is supported (by enabling the CONFIG_CPU_FREQ_BOOST_SW) extra sysfs attribute shows up: /sys/devices/system/cpu/cpu0/cpufreq/scaling_boost_frequencies [2] in which are listed only the boost frequencies. If the dts doesn't provide any values or as it is now no CPUFREQ_BOOST_FREQ flag is specified (at exynos4x12-cpufreq.c), then this list is empty. When boost is disabled the max freq (cpuinfo_max_freq) is in the range listed at [1]. When boost is enabled this value is the sum of freqs represented at [1] and [2]. By adding an extra attribute [2] we: 1. Indicate that boost is supported 2. List provided BOOST frequencies 3. Separate boost and non boost freqs > > > > > Intuitively the list without boost shouldn't have any frequency > > above the range when it's enabled :), that's what I was referring > > to. So I am not talking about any issue with user-space maintenance. > > > > Regards, > > Sudeep > > -- Best regards, Lukasz Majewski Samsung R&D Institute Poland (SRPOL) | Linux Platform Group