From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dominik Brodowski Subject: Re: your mail Date: Sat, 18 Sep 2010 17:56:06 +0200 Message-ID: <20100918155606.GA16269@isilmar-3.linta.de> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: Raj Kumar , linux-pm@lists.linux-foundation.org List-Id: linux-pm@vger.kernel.org Hi Raj, On Sat, Sep 18, 2010 at 11:36:16AM -0400, Alan Stern wrote: > > I have question regarding the CPU frequency subsystem through which the frequency of the CPU is scaled. > > > > e.g. If we have device driver (X device contains processor) that wants to scale its own processor based > > > > upon the workload, (DVFS driver for this processor is implemented and registered with cpufreq subsystem) > > > > then X device driver when detects waorkload, Can this X device driver call policy governor APIS for scaling clock or > > > > this X device driver can directly calls DVFS driver APIs directly? Best would be to register a cpufreq policy notifier, (cpufreq_register_notifier()), and then call cpufreq_update_policy() whenever the "X device driver" needs to modify its frequency constraints. In addition, it would be best to discuss this on the cpufreq mailing list at cpufreq@vger.kernel.org Best, Dominik