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 ESMTPS id 612DB2C009A for ; Sat, 15 Jun 2013 08:53:47 +1000 (EST) Message-ID: <1371250417.21896.17.camel@pasglop> Subject: Re: [PATCH] powerpc/sysfs: disable hotplug for the boot cpu From: Benjamin Herrenschmidt To: Zhao Chenhui Date: Sat, 15 Jun 2013 08:53:37 +1000 In-Reply-To: <20130613112552.GC7536@localhost.localdomain> References: <1369727984-21505-1-git-send-email-chenhui.zhao@freescale.com> <1369727984-21505-2-git-send-email-chenhui.zhao@freescale.com> <1370036984.3928.144.camel@pasglop> <20130603104315.GA1365@localhost.localdomain> <1371007522.8250.169.camel@pasglop> <20130613112552.GC7536@localhost.localdomain> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, 2013-06-13 at 19:25 +0800, Zhao Chenhui wrote: > Some multicore SoCs firstly boot up the cpu0 after warm reset. > In some suspend/resume cases, SoC will do a warm reset when resuming. > In order to ensure that the suspending and resuming is running > on a same cpu, cpu0 should be the last cpu to suspend. Here, cpu0 is > the boot_cpuid. Well, so: - In any case, your patch will break pseries, so it's not acceptable. - Why does it have to absolutely resume from the same CPU it suspended from ? Can't you have a little bit of code on the resuming CPU that checks if it's not online, poke an online one and goes back to sleep ? Cheers, Ben.