Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752719AbdFTVQh (ORCPT ); Tue, 20 Jun 2017 17:16:37 -0400 Received: from mail-it0-f66.google.com ([209.85.214.66]:33229 "EHLO mail-it0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751090AbdFTVQd (ORCPT ); Tue, 20 Jun 2017 17:16:33 -0400 MIME-Version: 1.0 In-Reply-To: References: <1979543.KIEJ8uyRaT@aspire.rjw.lan> <3454366.uzaJljlWGm@aspire.rjw.lan> <3689795.xuIczRHZsl@aspire.rjw.lan> <2026371.DVJN39QYJi@aspire.rjw.lan> From: "Rafael J. Wysocki" Date: Tue, 20 Jun 2017 23:16:32 +0200 X-Google-Sender-Auth: yHLiqWnsbR57nFupnLJ9PhT883g Message-ID: Subject: Re: [PATCH v2 3/3] ACPI / sleep: EC-based wakeup from suspend-to-idle on recent Dell systems To: Linus Torvalds Cc: "Rafael J. Wysocki" , "Rafael J. Wysocki" , Linux PM , Linux ACPI , Andy Shevchenko , Darren Hart , LKML , Srinivas Pandruvada , Mika Westerberg , Mario Limonciello , Tom Lanyon , =?UTF-8?B?SsOpcsO0bWUgZGUgQnJldGFnbmU=?= Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1753 Lines: 39 On Tue, Jun 20, 2017 at 4:00 AM, Linus Torvalds wrote: > On Tue, Jun 20, 2017 at 9:13 AM, Rafael J. Wysocki wrote: >> >> My understanding is that Windows uses the ACPI_FADT_LOW_POWER_S0 flag. >> It generally enables non-S3 suspend/resume when this flag is set and >> it doesn't touch S3 then. Keeping the EC GPE (and other GPEs for that >> matter) enabled over suspend/resume is part of that if my >> understanding is correct. >> >> During suspend we generally disable all GPEs that are not expected to >> generate wakeup events in order to avoid spurious wakeups, but we can >> try to keep them enabled if ACPI_FADT_LOW_POWER_S0 is set. That will >> reduce the ugliness, but the cost may be more energy used while >> suspended on some systems. > > I think trying to do something similar to what windows does is likely > the right thing, since that is (sadly) the only thing that tends to > get extensive testing still. > > Of course, different versions of Windows then probably do different > things, but I guess ACPI_FADT_LOW_POWER_S0 ends up being a good sign > of "new machine designed for windows 10", so it's probably a good > thing to trigger that behavior on. > > So I suspect it's worth testing, particularly if we're going to be in > the situation that a lot of machines are going to do this going > forward (ie the "all Dell" may end up being more than just Dell too? > Dell usually doesn't do particularly odd and out-of-the-norm design > choices like some vendors do). Well, involving the EC in power button events processing has not been a common practice so far. Anyway, I will replace this patch with something that ought to be more in line with what Windows does. Thanks, Rafael