From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 359C3DDED1 for ; Fri, 9 Feb 2007 09:24:12 +1100 (EST) Subject: Re: [PATCH 02/12] powermac: support G5 CPU hotplug From: Benjamin Herrenschmidt To: Johannes Berg In-Reply-To: <1170940494.4385.51.camel@johannes.berg> References: <20070207124536.963531000@sipsolutions.net> <20070207124610.392302000@sipsolutions.net> <1170940494.4385.51.camel@johannes.berg> Content-Type: text/plain Date: Fri, 09 Feb 2007 09:24:03 +1100 Message-Id: <1170973443.2620.371.camel@localhost.localdomain> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org, linux-pm@lists.osdl.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, 2007-02-08 at 14:14 +0100, Johannes Berg wrote: > On Wed, 2007-02-07 at 13:45 +0100, Johannes Berg wrote: > > > Except for the in-irq count hack I'm happy with this. I still haven't found > > where the in-hard-irq count is set to 1 in the down path during suspend or > > resume and other platforms do similar things so I'm inclined to leave this. > > Um, ok, so the hack breaks platforms that don't have paca, e.g. chrp32. > > Also, I finally figured out how the in-hard-irq count happens. The thing > is that when I try to turn off the CPU it actually doesn't really turn > off of course, so it ends up doing NAP and taking timer interrupts... > which goes irq_enter() and we happen to kill it afterwards. > > I have two ways of fixing this: > - just ignore it as we do now > - insert a "if (cpu_dead) return" into the timer interrupt function > > I prefer the latter because then we're guaranteed that whatever the > timer interrupt does we don't modify any state for/by the CPU that isn't > supposed to exist. Agreed. Ben.