From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexey Starikovskiy Subject: Re: So, what's the status on the recent patches here? Date: Fri, 18 Aug 2006 19:29:31 +0400 Message-ID: <44E5DCDB.1080306@linux.intel.com> References: <20060814200735.GC14099@kroah.com> <20060814224623.GH30814@redhat.com> <221e3d51950d20642b3655617527dc52@nomadgs.com> <1155638115.6736.135.camel@localhost> <20060815190439.GI7612@redhat.com> <1155733089.10017.17.camel@Dogbert.NOE.nokia.com> <20060817213903.GD6450@ucw.cz> <1155895341.22100.1.camel@Dogbert.NOE.nokia.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <1155895341.22100.1.camel@Dogbert.NOE.nokia.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.osdl.org Errors-To: linux-pm-bounces@lists.osdl.org To: Igor Stoppa Cc: linux-pm@lists.osdl.org, ext Pavel Machek , "Kucheria Amit (Nokia-M/Tampere)" List-Id: linux-pm@vger.kernel.org Igor Stoppa wrote: > On Fri, 2006-08-18 at 00:39 +0300, ext Pavel Machek wrote: >> Hi! >> >>>> If there are dependancies inherently linking core1 and core2, >> cpufreq >>>> should already be programming both parts. For example, the SA1100 >>>> driver programs both CPU and SDRAM controller. If there isn't any >>>> dependancy >>>> between them, I don't see the attraction of creating an artificial >> one >>>> in the way suggested for no real purpose. >>>> >>>> Things like voltage and frequency are closely tied together, so >>>> offering >>>> any means of controlling them independantly makes no sense afaics. >>> Yet a certain subsystem (for example an onboard camera, in a phone) >>> might require a higher voltage when it's active, effectively >> loosening >>> the tight coupling between freq and voltage that the porcessor is >>> enforcing. >> So... you expect userland to echo high > state before camera can be >> used? >> >> I'd rather have kernel automagically up the voltage when /dev/video0 >> is opened... > = > Not really, I meant that the CPU is not the only customer of power > domains (depend on the HW design), so the relation freq <-> voltage is > not always true. > = Then you need to introduce power domains and associate your devices with th= em, isn't it? So if your camera appears in the same domain with CPU, the voltage of that domain will go up either with camera=3Don, or CPU going to higher freq= uency.