From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: RT throttling and suspend/resume (was Re: [PATCH] i2c: omap: revert "i2c: omap: switch to threaded IRQ support") Date: Fri, 19 Oct 2012 16:00:27 +0200 Message-ID: <1350655227.2768.11.camel@twins> References: <20121016133356.GG21801@arwen.pp.htv.fi> <87ipaanljt.fsf_-_@deeprootsystems.com> <20121017140002.GI11394@arwen.pp.htv.fi> <20121017143534.GJ11394@arwen.pp.htv.fi> <87txtsitpt.fsf@deeprootsystems.com> <20121018055136.GF11137@arwen.pp.htv.fi> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Return-path: In-Reply-To: <20121018055136.GF11137-S8G//mZuvNWo5Im9Ml3/Zg@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: balbi-l0cyMroinI0@public.gmane.org Cc: Kevin Hilman , Thomas Gleixner , Shubhrajyoti Datta , Paul Walmsley , linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Shubhrajyoti D , Wolfram Sang , Ben Dooks , linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Russell King List-Id: linux-i2c@vger.kernel.org On Thu, 2012-10-18 at 08:51 +0300, Felipe Balbi wrote: > > So the primary question remains: is RT runtime supposed to include the > > time spent suspended? I suspect not. > > you might be right there, though we need Thomas or Peter to answer :-s re, sorry both tglx and I have been traveling, he still is, I'm trying to play catch-up :-) Anyway, yeah I'm somewhat surprised the clock is 'running' when the machine isn't. From what I could gather, this is !x86 hardware, right? x86 explicitly makes sure our clocks are 'stopped' during suspend, see commit cd7240c0b900eb6d690ccee088a6c9b46dae815a. Can you do something similar for ARM? A quick look at arch/arm/kernel/sched_clock.c shows there's already suspend/resume hooks, do they do the wrong thing?