From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: [PATCH] CPUFreq Support for PXA255 Date: Mon, 18 Jul 2005 12:02:06 +0100 Message-ID: <1121684526.4215.25.camel@icampbell-debian> References: <1121341256.10537.12.camel@icampbell-debian> <20050715164115.GA3240@isilmar.linta.de> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20050715164115.GA3240@isilmar.linta.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: cpufreq-bounces@lists.linux.org.uk Errors-To: cpufreq-bounces+glkc-cpufreq=gmane.org@lists.linux.org.uk Content-Type: text/plain; charset="us-ascii" To: Dominik Brodowski Cc: cpufreq@lists.linux.org.uk On Fri, 2005-07-15 at 18:41 +0200, Dominik Brodowski wrote: Thanks for you comments. I've snipped the bits for changes that I've already done. > > +static void pxa_select_freq_table(struct cpufreq_policy *policy, > > + pxa_freqs_t ** settings, > > + struct cpufreq_frequency_table > **table) > > +{ > [SNIP] > > +} > > As noted by Eric Piel already, please use a module parameter combined > with a sysfs file instead. > I've got it working with a module parameter so cpu_pxa.performance=1 allows selection of the performance table at boot time. This also creates /sys/module/cpu_pxa/parameters/performance which can be written to and takes effect on the next frequency change. Is this acceptable or should I look for a way to add a sysfs file to /sys/devices/system/cpu/cpu0/cpufreq? The advantage would be immediate application of the change (I think...) > > + cpumask_t cpus_allowed; > > Is this a SMP-capable platform? I don't really know to be honest -- there are SMP ARM's in the world but I don't know if that will ever extend to the PXA. I doubt it, but I've asked on the ARM kernel list. > Is the PXA just a sub-architecture of ARM? That's right, it's one of Intel's ARM implementations, it takes over from their StrongARM stuff. The PXA line is quite commonly found in PDAs. > > choice > > prompt "Default CPUFreq governor" > > - default CPU_FREQ_DEFAULT_GOV_USERSPACE if CPU_FREQ_SA1100 || CPU_FREQ_SA1110 > > + default CPU_FREQ_DEFAULT_GOV_USERSPACE if CPU_FREQ_SA1100 || CPU_FREQ_SA1110 || CPU_FREQ_PXA > > Why is that? I've no idea -- I just copied the StrongARM stuff. My guess is that someone decided that PERFORMANCE wasn't suitable as the default for an "embedded" platform. I think I'll probably just drop this chunk since you can always choose via config anyway. I've pinged the ARM list just in case there is a more pressing reason. Ian. -- Ian Campbell, Senior Design Engineer Web: http://www.arcom.com Arcom, Clifton Road, Direct: +44 (0)1223 403 465 Cambridge CB1 7EA, United Kingdom Phone: +44 (0)1223 411 200 _____________________________________________________________________ The message in this transmission is sent in confidence for the attention of the addressee only and should not be disclosed to any other party. Unauthorised recipients are requested to preserve this confidentiality. Please advise the sender if the addressee is not resident at the receiving end. Email to and from Arcom is automatically monitored for operational and lawful business reasons. This message has been virus scanned by MessageLabs.