From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755482AbZEFAN7 (ORCPT ); Tue, 5 May 2009 20:13:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752726AbZEFANu (ORCPT ); Tue, 5 May 2009 20:13:50 -0400 Received: from wf-out-1314.google.com ([209.85.200.171]:58468 "EHLO wf-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752700AbZEFANu convert rfc822-to-8bit (ORCPT ); Tue, 5 May 2009 20:13:50 -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> From: Kevin Hilman Organization: Deep Root Systems, LLC Date: Tue, 05 May 2009 17:13:48 -0700 In-Reply-To: <200905060127.24777.rjw@sisk.pl> (Rafael J. Wysocki's message of "Wed\, 6 May 2009 01\:27\:23 +0200") Message-ID: <87y6tb3x6r.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=iso-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org "Rafael J. Wysocki" writes: > On Wednesday 06 May 2009, Kevin Hilman wrote: >> Arve Hjønnevåg writes: >> >> > On Tue, May 5, 2009 at 8:52 AM, Kevin Hilman >> > wrote: >> >> Andrew Morton writes: >> >> >> >>> On Mon, 4 May 2009 17:27:04 -0700 Kevin Hilman wrote: >> >>> >> >>>> Interrupts that are flagged as wakeup sources via set_irq_wake() >> >>>> should not be disabled for suspend. >> >>>> >> >>> >> >>> Why not? >> >>> >> >> >> >> If an interrupt is a wakeup source, and it is disabled at the chip >> >> level, it will no longer generate interrupts, and thus no longer wake >> >> up the system. >> >> >> >> I'd be interested in hearing why wakeup interrupts should be disabled >> >> during suspend. > > That depends on whether or not they are used for anything else than wake-up. > >> >> [...] >> >> >>> >> >>> 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. Hmm, that's not normally what I think of as disabled. ;) > 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. Kevin