From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from imap.sh.mvista.com (unknown [63.81.120.155]) by ozlabs.org (Postfix) with ESMTP id DEFE8DDEF4 for ; Sat, 19 May 2007 01:04:34 +1000 (EST) Message-ID: <464DC0DC.7050809@ru.mvista.com> Date: Fri, 18 May 2007 19:06:04 +0400 From: Sergei Shtylyov MIME-Version: 1.0 To: Daniel Walker Subject: Re: [PATCH 2.6.21-rt2] PowerPC: decrementer clockevent driver References: <200705172142.26739.sshtylyov@ru.mvista.com> <8E44DB06-767D-4864-8D2C-6132E4D4370B@kernel.crashing.org> <464C99FF.8080404@ru.mvista.com> <135307ED-7125-4859-8594-4B5B900D92D6@kernel.crashing.org> <1179500217.20519.53.camel@imap.mvista.com> In-Reply-To: <1179500217.20519.53.camel@imap.mvista.com> Content-Type: text/plain; charset=us-ascii; format=flowed Cc: linuxppc-dev@ozlabs.org, tglx@linutronix.de, mingo@elte.hu, linux-kernel@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Daniel Walker wrote: >>I haven't looked at all the new clock/timer code, is there any >>utility in having support for more than one clock source? > There is if the main clocksource has some issues where it can't be used. You mean, having more than one clocksource is *useful* in this case? > On x86 there are lots of different issues with the clocks, so they have > to get switches once in a while. For instance, if the TSC changes > frequencies then it can't be used, or if the TSC stops in different > power states , it can't be used.. Yeah, and there's the rating systems for both clock sources/events. > Anything like that on PowerPC? Well, the decrementer frequency may change, at least in theory (if the bus clock changes). > Daniel WBR, Sergei