From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756123Ab1LEBST (ORCPT ); Sun, 4 Dec 2011 20:18:19 -0500 Received: from hqemgate04.nvidia.com ([216.228.121.35]:7772 "EHLO hqemgate04.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755896Ab1LEBSR (ORCPT ); Sun, 4 Dec 2011 20:18:17 -0500 X-PGP-Universal: processed; by hqnvupgp07.nvidia.com on Sun, 04 Dec 2011 17:18:17 -0800 Subject: Re: [PATCH v1] Input: tegra-kbc - report wakeup key for some platforms. From: riyer To: Dmitry Torokhov CC: "rydberg@euromail.se" , Stephen Warren , Laxman Dewangan , "linux-kernel@vger.kernel.org" , "linux-input@vger.kernel.org" , "linux-tegra@vger.kernel.org" In-Reply-To: <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> <20111204085038.GC14593@core.coreip.homeip.net> Content-Type: text/plain Date: Sun, 4 Dec 2011 17:18:17 -0800 Message-ID: <1323047897.3056.14.camel@riyer-dt2.nvidia.com> MIME-Version: 1.0 X-Mailer: Evolution 2.22.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Dmitry. Please find replies inline. On Sun, 2011-12-04 at 00:50 -0800, Dmitry Torokhov wrote: > 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 At this point syscoreops_resume has finished all its wakeup processing. > 3. System starts resuming devices > 4. User presses a key on the keypad while it is still suspended _and_ > registered as a wakeup source This will have no impact on the system and keypad ISR will not be invoked. > 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. The interrupt line we use to detect wakeup processing is the keypress interrupt which is disabled and will never cause the ISR invocation from a device interrupt(i.e. the PIC). In other words KBC isr gets invoked for 2 reasons a) FIFO interrupt is generated, which will not happen as long as scanning logic is disabled until kbc_resume executes. b) The syscoreops_resume codepath calls into the ISR after finding KBC was a wakesource. If this happens it will happen only when the kernel resumes from its suspend code path. > > Is this scenario not possible? > > Thanks. > With that being the case do you think the fix makes sense? Regards Rakesh