From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Tue, 30 Mar 2004 23:48:42 +0100 (BST) Received: from gateway-1237.mvista.com ([IPv6:::ffff:12.44.186.158]:31990 "EHLO av.mvista.com") by linux-mips.org with ESMTP id ; Tue, 30 Mar 2004 23:48:41 +0100 Received: from mvista.com (av [127.0.0.1]) by av.mvista.com (8.9.3/8.9.3) with ESMTP id OAA26284; Tue, 30 Mar 2004 14:48:36 -0800 Message-ID: <4069F942.5090202@mvista.com> Date: Tue, 30 Mar 2004 14:48:34 -0800 From: Pete Popov User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.6) Gecko/20040113 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Bob Lees CC: Dan Malek , linux-mips@linux-mips.org Subject: Re: Frequency (cpu speed) control on AU1100 References: <200403302137.38123.bob@diamond.demon.co.uk> <4069ED03.8060202@embeddededge.com> <200403302338.08735.bob@diamond.demon.co.uk> In-Reply-To: <200403302338.08735.bob@diamond.demon.co.uk> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 4702 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ppopov@mvista.com Precedence: bulk X-list: linux-mips Bob Lees wrote: >On Tuesday 30 March 2004 22:56, Dan Malek wrote: > > >>Bob Lees wrote: >> > ....I suspect I am >> >> >>>missing something somewhere, but I can't find any references to cpu speed >>>control for the MIPS processors, specically the au1x range. >>> >>> >>The Au1xxx has a PLL that multiplies the incoming 12 MHz clock up to the >>internal frequency. Just be aware there are lots of peripheral clocks >>and bus clocks derived from this internal frequency. There is code >>in the kernel power management to allow changing the frequency during >>operation of Linux, but I don't know how well it works today as I have >>not tested that for quite some time. >> >>Thanks. >> -- Dan >> >> > >Thanks Dan & Pete for the prompt response. > >I have tried the /proc/sys/pm/freq interface and by putting a bogomips calc >into power.c, it appears to indicate a change in core frequency. I think >your caution may be well founded as I got input overruns on the serial >console when I took the speed down to 84MHz, good character recognition >though, so it was an input buffer speed issue. > >Also I can see an approx 40-50mA change in current from 84 to 396MHz which >indicates something is changing. Supply is at 5 volts thru a simple switcher >down to 3.3 volts on the Aurora board. This is with nothing else running and >an nfs filesystem. As part of monitoring current I am seeing an anomoly: >namely after boot is complete and system is quiesent, at apparently 396MHz, >the current is 200mA, now after playing with the freq control the current at >396MHz stabalises at around 250mA. Verrry strange - any thoughts?? > > Is the 250mA after you've done a new power cycle, which doesn't make sense, or after you scale down to 84 and back up to 396MHz? >On another topic, what state is the IRDA driver in? > It works. Check out the IrDA readme on linux-mips.org:/pub/linux/mips/people/ppopov/2.4. I've tested two boards back to back using the network layer at FIR speeds, and a board to palm pilot using SIR. It's all in the readme. >This is building from the >patched 2.4.25 kernel on your site Dan. And a big thank you for this source >of a patched kernel and build tools. > > Pete