From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [Update][PATCH v2 01/12] PM / core: Add NEVER_SKIP and SMART_PREPARE driver flags Date: Fri, 20 Oct 2017 13:28:33 +0200 Message-ID: <9928366.cAI691llHG@aspire.rjw.lan> References: <3806130.B2KCK0tvef@aspire.rjw.lan> <1564009.ulyn1Ag4Ad@aspire.rjw.lan> <20171020113527.GA699@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: Received: from cloudserver094114.home.net.pl ([79.96.170.134]:58022 "EHLO cloudserver094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753006AbdJTLiP (ORCPT ); Fri, 20 Oct 2017 07:38:15 -0400 In-Reply-To: <20171020113527.GA699@kroah.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Greg Kroah-Hartman Cc: Linux PM , Lukas Wunner , Bjorn Helgaas , Alan Stern , LKML , Linux ACPI , Linux PCI , Linux Documentation , Mika Westerberg , Ulf Hansson , Andy Shevchenko , Kevin Hilman , Wolfram Sang , linux-i2c@vger.kernel.org, Lee Jones On Friday, October 20, 2017 1:35:27 PM CEST Greg Kroah-Hartman wrote: > On Fri, Oct 20, 2017 at 01:11:22PM +0200, Rafael J. Wysocki wrote: > > On Thursday, October 19, 2017 9:33:15 AM CEST Greg Kroah-Hartman wrote: > > > On Thu, Oct 19, 2017 at 01:17:31AM +0200, Rafael J. Wysocki wrote: > > > > From: Rafael J. Wysocki > > > > > > > > The motivation for this change is to provide a way to work around > > > > a problem with the direct-complete mechanism used for avoiding > > > > system suspend/resume handling for devices in runtime suspend. > > > > > > > > The problem is that some middle layer code (the PCI bus type and > > > > the ACPI PM domain in particular) returns positive values from its > > > > system suspend ->prepare callbacks regardless of whether the driver's > > > > ->prepare returns a positive value or 0, which effectively prevents > > > > drivers from being able to control the direct-complete feature. > > > > Some drivers need that control, however, and the PCI bus type has > > > > grown its own flag to deal with this issue, but since it is not > > > > limited to PCI, it is better to address it by adding driver flags at > > > > the core level. > > > > > > > > To that end, add a driver_flags field to struct dev_pm_info for flags > > > > that can be set by device drivers at the probe time to inform the PM > > > > core and/or bus types, PM domains and so on on the capabilities and/or > > > > preferences of device drivers. Also add two static inline helpers > > > > for setting that field and testing it against a given set of flags > > > > and make the driver core clear it automatically on driver remove > > > > and probe failures. > > > > > > > > Define and document two PM driver flags related to the direct- > > > > complete feature: NEVER_SKIP and SMART_PREPARE that can be used, > > > > respectively, to indicate to the PM core that the direct-complete > > > > mechanism should never be used for the device and to inform the > > > > middle layer code (bus types, PM domains etc) that it can only > > > > request the PM core to use the direct-complete mechanism for > > > > the device (by returning a positive value from its ->prepare > > > > callback) if it also has been requested by the driver. > > > > > > > > While at it, make the core check pm_runtime_suspended() when > > > > setting power.direct_complete so that it doesn't need to be > > > > checked by ->prepare callbacks. > > > > > > > > Signed-off-by: Rafael J. Wysocki > > > > > > Acked-by: Greg Kroah-Hartman > > > > Thanks! > > > > Does it also apply to the other patches in the series? > > > > I'd like to queue up the core patches for 4.15 as they are specifically > > designed to only affect the drivers that actually set the flags, so there > > shouldn't be any regression resulting from them, and I'd like to be > > able to start using the flags in drivers going forward. > > Yes, sorry, I thought I acked them, but you are right, I didn't: > > Acked-by: Greg Kroah-Hartman > > for all of them please. Thanks!