From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760014AbbAaBn2 (ORCPT ); Fri, 30 Jan 2015 20:43:28 -0500 Received: from szxga01-in.huawei.com ([119.145.14.64]:61518 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754202AbbAaBnZ (ORCPT ); Fri, 30 Jan 2015 20:43:25 -0500 Message-ID: <54CC3334.9010705@huawei.com> Date: Sat, 31 Jan 2015 09:43:16 +0800 From: "Yun Wu (Abel)" User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:11.0) Gecko/20120327 Thunderbird/11.0.1 MIME-Version: 1.0 To: Marc Zyngier CC: "tglx@linutronix.de" , "jason@lakedaemon.net" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH 5/5] irqchip: gicv3-its: add support for power down References: <1422604009-9248-1-git-send-email-wuyun.wu@huawei.com> <1422604009-9248-6-git-send-email-wuyun.wu@huawei.com> <54CBDA14.3010503@arm.com> In-Reply-To: <54CBDA14.3010503@arm.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.24.136] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/1/31 3:23, Marc Zyngier wrote: > On 30/01/15 07:46, Yun Wu wrote: >> Configurations of an ITS cannot be changed if the ITS is in an >> active status, so it might not be safe to perform a soft reboot >> with all the active ITSes un-disabled, etc. kexec. >> >> This patch will make sure all the active ITSes disabled before >> enabling them again without resetting ITS hardware. > > And what happens if the kernel crashes or gets rebooted from a watchdog? > Or if the bootloader messes things up? The ITS is in an unknown state > when we start again. > > Wouldn't it be better to address this instead? Enforcing an safe initial > state seems a better solution that relying on mechanisms that may not be > relevant for all cases. > Sure, checking the ITS state before initializing it is really a better solution, I will rewrite this patch and test again. Thanks, Abel