From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757363AbZEFOFD (ORCPT ); Wed, 6 May 2009 10:05:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755137AbZEFOEw (ORCPT ); Wed, 6 May 2009 10:04:52 -0400 Received: from wf-out-1314.google.com ([209.85.200.175]:39940 "EHLO wf-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754390AbZEFOEv (ORCPT ); Wed, 6 May 2009 10:04:51 -0400 To: "Rafael J. Wysocki" Cc: Arve =?iso-8859-1?Q?Hj=F8nnev=E5g?= , Andrew Morton , linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Linus Torvalds , Ingo Molnar Subject: Re: [PATCH] PM: suspend_device_irqs(): don't disable wakeup IRQs References: <1241483224-7113-1-git-send-email-khilman@deeprootsystems.com> <87eiv35eg6.fsf@deeprootsystems.com> <200905060127.24777.rjw@sisk.pl> <87y6tb3x6r.fsf@deeprootsystems.com> From: Kevin Hilman Organization: Deep Root Systems, LLC Date: Wed, 06 May 2009 07:04:48 -0700 In-Reply-To: <87y6tb3x6r.fsf@deeprootsystems.com> (Kevin Hilman's message of "Tue\, 05 May 2009 17\:13\:48 -0700") Message-ID: <871vr22upr.fsf@deeprootsystems.com> User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Kevin Hilman writes: > "Rafael J. Wysocki" writes: > >> On Wednesday 06 May 2009, Kevin Hilman wrote: [...] >>> >>> [...] >>> >>> >>> >>> >>> If this fixes some bug then please provide a description of that bug? >>> >> >>> >> The bug is that on TI OMAP, interrupts that are used for wakeup events >>> >> are disabled by this code causing the system to no longer wake up. >>> > >>> > What do you do if the interrupt triggers right after your driver has >>> > returned from its late suspend hook? >>> >>> If it's a wakeup IRQ, I assume you want it to prevent suspend. >>> >>> But I don't see how that can happen in the current code. IIUC, by the >>> time your late suspend hook is run, your device IRQ is already >>> disabled, so it won't trigger an interrupt that will be caught by >>> check_wakeup_irqs() anyways. >> >> My understanding of __disable_irq() was that it didn't actually disable the >> IRQ at the hardware level, allowing the CPU to actually receive the interrupt >> and acknowledge it, but preventing the device driver for receiving it. > >> Does it work differently on the affected systems? > > Yes. > > __disable_irq() calls the irq_chip's disable method which is platform > specific. On OMAP, this masks the IRQ at the hardware level > preventing the CPU from seeing the interrupt. Looking at x86, the i8259 disable hook also seems to mask the IRQ at the PIC level. The various IO-APIC irq_chips do not have a disable hook so the __disable_irq() here is a NOP. Kevin