From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752500Ab1LDIus (ORCPT ); Sun, 4 Dec 2011 03:50:48 -0500 Received: from mail-iy0-f174.google.com ([209.85.210.174]:54822 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751836Ab1LDIup (ORCPT ); Sun, 4 Dec 2011 03:50:45 -0500 Date: Sun, 4 Dec 2011 00:50:38 -0800 From: Dmitry Torokhov To: Rakesh Iyer Cc: "rydberg@euromail.se" , Stephen Warren , Laxman Dewangan , "linux-kernel@vger.kernel.org" , "linux-input@vger.kernel.org" , "linux-tegra@vger.kernel.org" Subject: Re: [PATCH v1] Input: tegra-kbc - report wakeup key for some platforms. Message-ID: <20111204085038.GC14593@core.coreip.homeip.net> References: <1322685811-14060-1-git-send-email-riyer@nvidia.com> <20111130212022.GB3108@core.coreip.homeip.net> <1FC56210173BB445BD77F608D6FB8D034F3D1BB4BD@HQMAIL03.nvidia.com> <20111201072649.GE16816@core.coreip.homeip.net> <1FC56210173BB445BD77F608D6FB8D034F3D1BB4C9@HQMAIL03.nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1FC56210173BB445BD77F608D6FB8D034F3D1BB4C9@HQMAIL03.nvidia.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Rakesh, On Thu, Dec 01, 2011 at 01:09:59PM -0800, Rakesh Iyer wrote: > Hello Dmitry. > > Sorry for the wrap issue, my Outlook does not seem to obey the settings. > > I wanted to explain the tegra system resume path implementation so I can justify > why I am doing this complicated fix and why I feel it will guarantee the resume > is due to keypress. > > The tegra wake resume code is registered as a syscore ops. > When the system is resumed due to a wake event, the suspend_enter (after wakeup) > routine will invoke the tegra syscoreops_resume method and that routine will propagate > the wake event to the individual ISR's through genirq. > If kbc was wake source, kbc_isr will be invoked in this execution path. > > If system is resumed due to other reason, the tegra_syscoreops_resume code will not > find the event. Consider the following sequence: 1. Something other than keyboard generates wakeup event 2. It's IRQ fires up and gets serviced 3. System starts resuming devices 4. User presses a key on the keypad while it is still suspended _and_ registered as a wakeup source 5. Keypad's ISR runs as well and you decide that KEY_POWER should be reported even though keypad wasn't the real reason the system woke up. Is this scenario not possible? Thanks. -- Dmitry