From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765774AbXF1VKg (ORCPT ); Thu, 28 Jun 2007 17:10:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761166AbXF1VKa (ORCPT ); Thu, 28 Jun 2007 17:10:30 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:56552 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761069AbXF1VK3 (ORCPT ); Thu, 28 Jun 2007 17:10:29 -0400 From: "Rafael J. Wysocki" To: Andrew Morton Subject: Re: [PATCH] PM: Introduce set_target method in pm_ops Date: Thu, 28 Jun 2007 23:17:21 +0200 User-Agent: KMail/1.9.5 Cc: David Brownell , Pavel Machek , Johannes Berg , Len Brown , LKML References: <200706272356.29475.rjw@sisk.pl> <20070628133724.31cc9ace.akpm@linux-foundation.org> In-Reply-To: <20070628133724.31cc9ace.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200706282317.22091.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thursday, 28 June 2007 22:37, Andrew Morton wrote: > On Wed, 27 Jun 2007 23:56:28 +0200 > "Rafael J. Wysocki" wrote: > > > [Please consider as 2.6.22 material.] > > The patch tries to patch the function suspend_devices_and_enter() which is > introduced by pm-reduce-code-duplication-between-mainc-and-userc.patch, > which won't be in 2.6.22. Oh, thanks for spotting that, I've overlooked it. Sorry. The updated version below is on top of vanilla 2.6.22-rc6. It's almost the same as the original one except for the 'goto Thaw' in suspend_prepare() (instead of 'return error' which would be wrong). It breaks pm-reduce-code-duplication-between-mainc-and-userc.patch quite a bit, but I'll rework and resend that patch in a while (please drop it for now). Greetings, Rafael --- From: Rafael J. Wysocki Commit 52ade9b3b97fd3bea42842a056fe0786c28d0555 changed the suspend code ordering to execute pm_ops->prepare() after the device model per-device .suspend() calls in order to fix some ACPI-related issues. Unfortunately, it broke the at91 platform which assumed that pm_ops->prepare() would be called before suspending devices. at91 used pm_ops->prepare() to get notified of the target system sleep state, so that it could use this information while suspending devices. However, with the current suspend code ordering pm_ops->prepare() is called too late for this purpose. Thus, at91 needs an additional method in 'struct pm_ops' that will be used for notifying the platform of the target system sleep state. Moreover, in the future such a method will also be needed by ACPI. This patch adds the .set_target() method to 'struct pm_ops' and makes the suspend code call it, if implemented, before executing the device model per-device .suspend() calls. It also modifies the at91 code to use pm_ops->set_target() instead of pm_ops->prepare(). Signed-off-by: Rafael J. Wysocki Acked-by: David Brownell --- arch/arm/mach-at91/pm.c | 4 +- include/linux/pm.h | 66 +++++++++++++++++++++++++++++++++++------------- kernel/power/main.c | 6 +++- 3 files changed, 56 insertions(+), 20 deletions(-) Index: linux-2.6.22-rc6/include/linux/pm.h =================================================================== --- linux-2.6.22-rc6.orig/include/linux/pm.h 2007-06-28 22:55:13.000000000 +0200 +++ linux-2.6.22-rc6/include/linux/pm.h 2007-06-28 22:55:28.000000000 +0200 @@ -110,37 +110,67 @@ typedef int __bitwise suspend_state_t; #define PM_SUSPEND_MAX ((__force suspend_state_t) 4) /** - * struct pm_ops - Callbacks for managing platform dependent suspend states. - * @valid: Callback to determine whether the given state can be entered. - * Valid states are advertised in /sys/power/state but can still - * be rejected by prepare or enter if the conditions aren't right. - * There is a %pm_valid_only_mem function available that can be assigned - * to this if you only implement mem sleep. + * struct pm_ops - Callbacks for managing platform dependent system sleep + * states. * - * @prepare: Prepare the platform for the given suspend state. Can return a - * negative error code if necessary. - * - * @enter: Enter the given suspend state, must be assigned. Can return a - * negative error code if necessary. - * - * @finish: Called when the system has left the given state and all devices - * are resumed. The return value is ignored. + * @valid: Callback to determine if given system sleep state is supported by + * the platform. + * Valid (ie. supported) states are advertised in /sys/power/state. Note + * that it still may be impossible to enter given system sleep state if the + * conditions aren't right. + * There is the %pm_valid_only_mem function available that can be assigned + * to this if the platform only supports mem sleep. + * + * @set_target: Tell the platform which system sleep state is going to be + * entered. + * @set_target() is executed right prior to suspending devices. The + * information conveyed to the platform code by @set_target() should be + * disregarded by the platform as soon as @finish() is executed and if + * @prepare() fails. If @set_target() fails (ie. returns nonzero), + * @prepare(), @enter() and @finish() will not be called by the PM core. + * This callback is optional. However, if it is implemented, the argument + * passed to @prepare(), @enter() and @finish() is meaningless and should + * be ignored. + * + * @prepare: Prepare the platform for entering the system sleep state indicated + * by @set_target() or represented by the argument if @set_target() is not + * implemented. + * @prepare() is called right after devices have been suspended (ie. the + * appropriate .suspend() method has been executed for each device) and + * before the nonboot CPUs are disabled (it is executed with IRQs enabled). + * This callback is optional. It returns 0 on success or a negative + * error code otherwise, in which case the system cannot enter the desired + * sleep state (@enter() and @finish() will not be called in that case). + * + * @enter: Enter the system sleep state indicated by @set_target() or + * represented by the argument if @set_target() is not implemented. + * This callback is mandatory. It returns 0 on success or a negative + * error code otherwise, in which case the system cannot enter the desired + * sleep state. + * + * @finish: Called when the system has just left a sleep state, right after + * the nonboot CPUs have been enabled and before devices are resumed (it is + * executed with IRQs enabled). If @set_target() is not implemented, the + * argument represents the sleep state being left. + * This callback is optional, but should be implemented by the platforms + * that implement @prepare(). If implemented, it is always called after + * @enter() (even if @enter() fails). */ struct pm_ops { int (*valid)(suspend_state_t state); + int (*set_target)(suspend_state_t state); int (*prepare)(suspend_state_t state); int (*enter)(suspend_state_t state); int (*finish)(suspend_state_t state); }; +extern struct pm_ops *pm_ops; + /** * pm_set_ops - set platform dependent power management ops * @pm_ops: The new power management operations to set. */ extern void pm_set_ops(struct pm_ops *pm_ops); -extern struct pm_ops *pm_ops; -extern int pm_suspend(suspend_state_t state); - extern int pm_valid_only_mem(suspend_state_t state); /** @@ -161,6 +191,8 @@ extern void arch_suspend_disable_irqs(vo */ extern void arch_suspend_enable_irqs(void); +extern int pm_suspend(suspend_state_t state); + /* * Device power management */ Index: linux-2.6.22-rc6/kernel/power/main.c =================================================================== --- linux-2.6.22-rc6.orig/kernel/power/main.c 2007-06-28 22:55:13.000000000 +0200 +++ linux-2.6.22-rc6/kernel/power/main.c 2007-06-28 22:57:07.000000000 +0200 @@ -15,7 +15,6 @@ #include #include #include -#include #include #include #include @@ -97,6 +96,11 @@ static int suspend_prepare(suspend_state } } + if (pm_ops->set_target) { + error = pm_ops->set_target(state); + if (error) + goto Thaw; + } suspend_console(); error = device_suspend(PMSG_SUSPEND); if (error) { Index: linux-2.6.22-rc6/arch/arm/mach-at91/pm.c =================================================================== --- linux-2.6.22-rc6.orig/arch/arm/mach-at91/pm.c 2007-06-28 22:54:11.000000000 +0200 +++ linux-2.6.22-rc6/arch/arm/mach-at91/pm.c 2007-06-28 22:55:28.000000000 +0200 @@ -53,7 +53,7 @@ static suspend_state_t target_state; /* * Called after processes are frozen, but before we shutdown devices. */ -static int at91_pm_prepare(suspend_state_t state) +static int at91_pm_set_target(suspend_state_t state) { target_state = state; return 0; @@ -201,7 +201,7 @@ error: static struct pm_ops at91_pm_ops ={ .valid = at91_pm_valid_state, - .prepare = at91_pm_prepare, + .set_target = at91_pm_set_target, .enter = at91_pm_enter, };