On Fri 2010-04-30 15:36:54, Arve Hj??nnev??g wrote: > Adds /sys/power/policy that selects the behaviour of /sys/power/state. > After setting the policy to opportunistic, writes to /sys/power/state > become non-blocking requests that specify which suspend state to enter > when no suspend blockers are active. A special state, "on", stops the > process by activating the "main" suspend blocker. > > Signed-off-by: Arve Hj??nnev??g <arve@xxxxxxxxxxx> Also note that this patch mixes up adding new in-kernel interface with adding new userland API. The in-kernel interface seems to be sane and it would be nice to merge it soon, unfortunately the strange userland API is in the same patch :-(. > --- > Documentation/power/opportunistic-suspend.txt | 119 +++++++++++ > include/linux/suspend_blocker.h | 64 ++++++ > kernel/power/Kconfig | 16 ++ > kernel/power/Makefile | 1 + > kernel/power/main.c | 92 ++++++++- > kernel/power/power.h | 9 + > kernel/power/suspend.c | 4 +- > kernel/power/suspend_blocker.c | 261 +++++++++++++++++++++++++ > 8 files changed, 559 insertions(+), 7 deletions(-) > create mode 100644 Documentation/power/opportunistic-suspend.txt > create mode 100755 include/linux/suspend_blocker.h > create mode 100644 kernel/power/suspend_blocker.c > > diff --git a/Documentation/power/opportunistic-suspend.txt b/Documentation/power/opportunistic-suspend.txt > new file mode 100644 > index 0000000..3d060e8 > --- /dev/null > +++ b/Documentation/power/opportunistic-suspend.txt > @@ -0,0 +1,119 @@ > +Opportunistic Suspend > +===================== > + > +Opportunistic suspend is a feature allowing the system to be suspended (ie. put > +into one of the available sleep states) automatically whenever it is regarded > +as idle. The suspend blockers framework described below is used to determine > +when that happens. > + > +The /sys/power/policy sysfs attribute is used to switch the system between the > +opportunistic and "forced" suspend behavior, where in the latter case the > +system is only suspended if a specific value, corresponding to one of the > +available system sleep states, is written into /sys/power/state. However, in > +the former, opportunistic, case the system is put into the sleep state > +corresponding to the value written to /sys/power/state whenever there are no > +active suspend blockers. The default policy is "forced". Also, suspend blockers > +do not affect sleep states entered from idle. > + > +When the policy is "opportunisic", there is a special value, "on", that can be > +written to /sys/power/state. This will block the automatic sleep request, as if > +a suspend blocker was used by a device driver. This way the opportunistic > +suspend may be blocked by user space whithout switching back to the "forced" > +mode. > + > +A suspend blocker is an object used to inform the PM subsystem when the system > +can or cannot be suspended in the "opportunistic" mode (the "forced" mode > +ignores suspend blockers). To use it, a device driver creates a struct > +suspend_blocker that must be initialized with suspend_blocker_init(). Before > +freeing the suspend_blocker structure or its name, suspend_blocker_destroy() > +must be called on it. > + > +A suspend blocker is activated using suspend_block(), which prevents the PM > +subsystem from putting the system into the requested sleep state in the > +"opportunistic" mode until the suspend blocker is deactivated with > +suspend_unblock(). Multiple suspend blockers may be active simultaneously, and > +the system will not suspend as long as at least one of them is active. > + > +If opportunistic suspend is already in progress when suspend_block() is called, > +it will abort the suspend, unless suspend_ops->enter has already been > +executed. If suspend is aborted this way, the system is usually not fully > +operational at that point. The suspend callbacks of some drivers may still be > +running and it usually takes time to restore the system to the fully operational > +state. > + > +Here's an example showing how a cell phone or other embedded system can handle > +keystrokes (or other input events) in the presence of suspend blockers. Use > +set_irq_wake or a platform specific api to make sure the keypad interrupt wakes > +up the cpu. Once the keypad driver has resumed, the sequence of events can look > +like this: > + > +- The Keypad driver gets an interrupt. It then calls suspend_block on the > + keypad-scan suspend_blocker and starts scanning the keypad matrix. > +- The keypad-scan code detects a key change and reports it to the input-event > + driver. > +- The input-event driver sees the key change, enqueues an event, and calls > + suspend_block on the input-event-queue suspend_blocker. > +- The keypad-scan code detects that no keys are held and calls suspend_unblock > + on the keypad-scan suspend_blocker. > +- The user-space input-event thread returns from select/poll, calls > + suspend_block on the process-input-events suspend_blocker and then calls read > + on the input-event device. > +- The input-event driver dequeues the key-event and, since the queue is now > + empty, it calls suspend_unblock on the input-event-queue suspend_blocker. > +- The user-space input-event thread returns from read. If it determines that > + the key should be ignored, it calls suspend_unblock on the > + process_input_events suspend_blocker and then calls select or poll. The > + system will automatically suspend again, since now no suspend blockers are > + active. > + > +If the key that was pressed instead should preform a simple action (for example, > +adjusting the volume), this action can be performed right before calling > +suspend_unblock on the process_input_events suspend_blocker. However, if the key > +triggers a longer-running action, that action needs its own suspend_blocker and > +suspend_block must be called on that suspend blocker before calling > +suspend_unblock on the process_input_events suspend_blocker. > + > + Key pressed Key released > + | | > +keypad-scan ++++++++++++++++++ > +input-event-queue +++ +++ > +process-input-events +++ +++ > + > + > +Driver API > +========== > + > +A driver can use the suspend block api by adding a suspend_blocker variable to > +its state and calling suspend_blocker_init. For instance: > +struct state { > + struct suspend_blocker suspend_blocker; > +} > + > +init() { > + suspend_blocker_init(&state->suspend_blocker, "suspend-blocker-name"); > +} > + > +Before freeing the memory, suspend_blocker_destroy must be called: > + > +uninit() { > + suspend_blocker_destroy(&state->suspend_blocker); > +} > + > +When the driver determines that it needs to run (usually in an interrupt > +handler) it calls suspend_block: > + suspend_block(&state->suspend_blocker); > + > +When it no longer needs to run it calls suspend_unblock: > + suspend_unblock(&state->suspend_blocker); > + > +Calling suspend_block when the suspend blocker is active or suspend_unblock when > +it is not active has no effect (i.e., these functions don't nest). This allows > +drivers to update their state and call suspend suspend_block or suspend_unblock > +based on the result. > +For instance: > + > +if (list_empty(&state->pending_work)) > + suspend_unblock(&state->suspend_blocker); > +else > + suspend_block(&state->suspend_blocker); > + > diff --git a/include/linux/suspend_blocker.h b/include/linux/suspend_blocker.h > new file mode 100755 > index 0000000..f9928cc > --- /dev/null > +++ b/include/linux/suspend_blocker.h > @@ -0,0 +1,64 @@ > +/* include/linux/suspend_blocker.h > + * > + * Copyright (C) 2007-2009 Google, Inc. > + * > + * This software is licensed under the terms of the GNU General Public > + * License version 2, as published by the Free Software Foundation, and > + * may be copied, distributed, and modified under those terms. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + */ > + > +#ifndef _LINUX_SUSPEND_BLOCKER_H > +#define _LINUX_SUSPEND_BLOCKER_H > + > +#include <linux/list.h> > + > +/** > + * struct suspend_blocker - the basic suspend_blocker structure > + * @link: List entry for active or inactive list. > + * @flags: Tracks initialized and active state. > + * @name: Name used for debugging. > + * > + * When a suspend_blocker is active it prevents the system from entering > + * opportunistic suspend. > + * > + * The suspend_blocker structure must be initialized by suspend_blocker_init() > + */ > + > +struct suspend_blocker { > +#ifdef CONFIG_OPPORTUNISTIC_SUSPEND > + struct list_head link; > + int flags; > + const char *name; > +#endif > +}; > + > +#ifdef CONFIG_OPPORTUNISTIC_SUSPEND > + > +void suspend_blocker_init(struct suspend_blocker *blocker, const char *name); > +void suspend_blocker_destroy(struct suspend_blocker *blocker); > +void suspend_block(struct suspend_blocker *blocker); > +void suspend_unblock(struct suspend_blocker *blocker); > +bool suspend_blocker_is_active(struct suspend_blocker *blocker); > +bool suspend_is_blocked(void); > + > +#else > + > +static inline void suspend_blocker_init(struct suspend_blocker *blocker, > + const char *name) {} > +static inline void suspend_blocker_destroy(struct suspend_blocker *blocker) {} > +static inline void suspend_block(struct suspend_blocker *blocker) {} > +static inline void suspend_unblock(struct suspend_blocker *blocker) {} > +static inline bool suspend_blocker_is_active(struct suspend_blocker *bl) > + { return 0; } > +static inline bool suspend_is_blocked(void) { return 0; } > + > +#endif > + > +#endif > + > diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig > index 5c36ea9..55a06a1 100644 > --- a/kernel/power/Kconfig > +++ b/kernel/power/Kconfig > @@ -130,6 +130,22 @@ config SUSPEND_FREEZER > > Turning OFF this setting is NOT recommended! If in doubt, say Y. > > +config OPPORTUNISTIC_SUSPEND > + bool "Suspend blockers" > + depends on PM_SLEEP > + select RTC_LIB > + default n > + ---help--- > + Opportunistic sleep support. Allows the system to be put into a sleep > + state opportunistically, if it doesn't do any useful work at the > + moment. The PM subsystem is switched into this mode of operation by > + writing "opportunistic" into /sys/power/policy, while writing > + "forced" to this file turns the opportunistic suspend feature off. > + In the "opportunistic" mode suspend blockers are used to determine > + when to suspend the system and the value written to /sys/power/state > + determines the sleep state the system will be put into when there are > + no active suspend blockers. > + > config HIBERNATION_NVS > bool > > diff --git a/kernel/power/Makefile b/kernel/power/Makefile > index 4319181..ee5276d 100644 > --- a/kernel/power/Makefile > +++ b/kernel/power/Makefile > @@ -7,6 +7,7 @@ obj-$(CONFIG_PM) += main.o > obj-$(CONFIG_PM_SLEEP) += console.o > obj-$(CONFIG_FREEZER) += process.o > obj-$(CONFIG_SUSPEND) += suspend.o > +obj-$(CONFIG_OPPORTUNISTIC_SUSPEND) += suspend_blocker.o > obj-$(CONFIG_PM_TEST_SUSPEND) += suspend_test.o > obj-$(CONFIG_HIBERNATION) += hibernate.o snapshot.o swap.o user.o > obj-$(CONFIG_HIBERNATION_NVS) += hibernate_nvs.o > diff --git a/kernel/power/main.c b/kernel/power/main.c > index b58800b..030ecdc 100644 > --- a/kernel/power/main.c > +++ b/kernel/power/main.c > @@ -12,6 +12,7 @@ > #include <linux/string.h> > #include <linux/resume-trace.h> > #include <linux/workqueue.h> > +#include <linux/suspend_blocker.h> > > #include "power.h" > > @@ -20,6 +21,27 @@ DEFINE_MUTEX(pm_mutex); > unsigned int pm_flags; > EXPORT_SYMBOL(pm_flags); > > +struct policy { > + const char *name; > + bool (*valid_state)(suspend_state_t state); > + int (*set_state)(suspend_state_t state); > +}; > +static struct policy policies[] = { > + { > + .name = "forced", > + .valid_state = valid_state, > + .set_state = enter_state, > + }, > +#ifdef CONFIG_OPPORTUNISTIC_SUSPEND > + { > + .name = "opportunistic", > + .valid_state = request_suspend_valid_state, > + .set_state = request_suspend_state, > + }, > +#endif > +}; > +static int policy; > + > #ifdef CONFIG_PM_SLEEP > > /* Routines for PM-transition notifications */ > @@ -146,6 +168,12 @@ struct kobject *power_kobj; > * > * store() accepts one of those strings, translates it into the > * proper enumerated value, and initiates a suspend transition. > + * > + * If policy is set to opportunistic, store() does not block until the > + * system resumes, and it will try to re-enter the state until another > + * state is requested. Suspend blockers are respected and the requested > + * state will only be entered when no suspend blockers are active. > + * Write "on" to cancel. > */ > static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr, > char *buf) > @@ -155,12 +183,13 @@ static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr, > int i; > > for (i = 0; i < PM_SUSPEND_MAX; i++) { > - if (pm_states[i] && valid_state(i)) > + if (pm_states[i] && policies[policy].valid_state(i)) > s += sprintf(s,"%s ", pm_states[i]); > } > #endif > #ifdef CONFIG_HIBERNATION > - s += sprintf(s, "%s\n", "disk"); > + if (!policy) > + s += sprintf(s, "%s\n", "disk"); > #else > if (s != buf) > /* convert the last space to a newline */ > @@ -173,7 +202,7 @@ static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr, > const char *buf, size_t n) > { > #ifdef CONFIG_SUSPEND > - suspend_state_t state = PM_SUSPEND_STANDBY; > + suspend_state_t state = PM_SUSPEND_ON; > const char * const *s; > #endif > char *p; > @@ -184,7 +213,7 @@ static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr, > len = p ? p - buf : n; > > /* First, check if we are requested to hibernate */ > - if (len == 4 && !strncmp(buf, "disk", len)) { > + if (len == 4 && !strncmp(buf, "disk", len) && !policy) { > error = hibernate(); > goto Exit; > } > @@ -195,7 +224,7 @@ static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr, > break; > } > if (state < PM_SUSPEND_MAX && *s) > - error = enter_state(state); > + error = policies[policy].set_state(state); > #endif > > Exit: > @@ -204,6 +233,55 @@ static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr, > > power_attr(state); > > +/** > + * policy - set policy for state > + */ > + > +static ssize_t policy_show(struct kobject *kobj, > + struct kobj_attribute *attr, char *buf) > +{ > + char *s = buf; > + int i; > + > + for (i = 0; i < ARRAY_SIZE(policies); i++) { > + if (i == policy) > + s += sprintf(s, "[%s] ", policies[i].name); > + else > + s += sprintf(s, "%s ", policies[i].name); > + } > + if (s != buf) > + /* convert the last space to a newline */ > + *(s-1) = '\n'; > + return (s - buf); > +} > + > +static ssize_t policy_store(struct kobject *kobj, > + struct kobj_attribute *attr, > + const char *buf, size_t n) > +{ > + const char *s; > + char *p; > + int len; > + int i; > + > + p = memchr(buf, '\n', n); > + len = p ? p - buf : n; > + > + for (i = 0; i < ARRAY_SIZE(policies); i++) { > + s = policies[i].name; > + if (s && len == strlen(s) && !strncmp(buf, s, len)) { > + mutex_lock(&pm_mutex); > + policies[policy].set_state(PM_SUSPEND_ON); > + policy = i; > + mutex_unlock(&pm_mutex); > + return n; > + } > + } > + return -EINVAL; > +} > + > +power_attr(policy); > + > #ifdef CONFIG_PM_TRACE > int pm_trace_enabled; > > @@ -231,6 +309,7 @@ power_attr(pm_trace); > > static struct attribute * g[] = { > &state_attr.attr, > + &policy_attr.attr, > #ifdef CONFIG_PM_TRACE > &pm_trace_attr.attr, > #endif > @@ -247,7 +326,7 @@ static struct attribute_group attr_group = { > .attrs = g, > }; > > -#ifdef CONFIG_PM_RUNTIME > +#if defined(CONFIG_PM_RUNTIME) || defined(CONFIG_OPPORTUNISTIC_SUSPEND) > struct workqueue_struct *pm_wq; > EXPORT_SYMBOL_GPL(pm_wq); > > @@ -266,6 +345,7 @@ static int __init pm_init(void) > int error = pm_start_workqueue(); > if (error) > return error; > + suspend_block_init(); > power_kobj = kobject_create_and_add("power", NULL); > if (!power_kobj) > return -ENOMEM; > diff --git a/kernel/power/power.h b/kernel/power/power.h > index 46c5a26..67d10fd 100644 > --- a/kernel/power/power.h > +++ b/kernel/power/power.h > @@ -236,3 +236,12 @@ static inline void suspend_thaw_processes(void) > { > } > #endif > + > +/* kernel/power/suspend_block.c */ > +extern int request_suspend_state(suspend_state_t state); > +extern bool request_suspend_valid_state(suspend_state_t state); > +#ifdef CONFIG_OPPORTUNISTIC_SUSPEND > +extern void __init suspend_block_init(void); > +#else > +static inline void suspend_block_init(void) {} > +#endif > diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c > index 56e7dbb..dc42006 100644 > --- a/kernel/power/suspend.c > +++ b/kernel/power/suspend.c > @@ -16,10 +16,12 @@ > #include <linux/cpu.h> > #include <linux/syscalls.h> > #include <linux/gfp.h> > +#include <linux/suspend_blocker.h> > > #include "power.h" > > const char *const pm_states[PM_SUSPEND_MAX] = { > + [PM_SUSPEND_ON] = "on", > [PM_SUSPEND_STANDBY] = "standby", > [PM_SUSPEND_MEM] = "mem", > }; > @@ -157,7 +159,7 @@ static int suspend_enter(suspend_state_t state) > > error = sysdev_suspend(PMSG_SUSPEND); > if (!error) { > - if (!suspend_test(TEST_CORE)) > + if (!suspend_is_blocked() && !suspend_test(TEST_CORE)) > error = suspend_ops->enter(state); > sysdev_resume(); > } > diff --git a/kernel/power/suspend_blocker.c b/kernel/power/suspend_blocker.c > new file mode 100644 > index 0000000..2c58b21 > --- /dev/null > +++ b/kernel/power/suspend_blocker.c > @@ -0,0 +1,261 @@ > +/* kernel/power/suspend_blocker.c > + * > + * Copyright (C) 2005-2010 Google, Inc. > + * > + * This software is licensed under the terms of the GNU General Public > + * License version 2, as published by the Free Software Foundation, and > + * may be copied, distributed, and modified under those terms. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + */ > + > +#include <linux/module.h> > +#include <linux/rtc.h> > +#include <linux/suspend.h> > +#include <linux/suspend_blocker.h> > +#include "power.h" > + > +extern struct workqueue_struct *pm_wq; > + > +enum { > + DEBUG_EXIT_SUSPEND = 1U << 0, > + DEBUG_WAKEUP = 1U << 1, > + DEBUG_USER_STATE = 1U << 2, > + DEBUG_SUSPEND = 1U << 3, > + DEBUG_SUSPEND_BLOCKER = 1U << 4, > +}; > +static int debug_mask = DEBUG_EXIT_SUSPEND | DEBUG_WAKEUP | DEBUG_USER_STATE; > +module_param_named(debug_mask, debug_mask, int, S_IRUGO | S_IWUSR | S_IWGRP); > + > +#define SB_INITIALIZED (1U << 8) > +#define SB_ACTIVE (1U << 9) > + > +static DEFINE_SPINLOCK(list_lock); > +static DEFINE_SPINLOCK(state_lock); > +static LIST_HEAD(inactive_blockers); > +static LIST_HEAD(active_blockers); > +static int current_event_num; > +struct suspend_blocker main_suspend_blocker; > +static suspend_state_t requested_suspend_state = PM_SUSPEND_MEM; > +static bool enable_suspend_blockers; > + > +#define pr_info_time(fmt, args...) \ > + do { \ > + struct timespec ts; \ > + struct rtc_time tm; \ > + getnstimeofday(&ts); \ > + rtc_time_to_tm(ts.tv_sec, &tm); \ > + pr_info(fmt "(%d-%02d-%02d %02d:%02d:%02d.%09lu UTC)\n" , \ > + args, \ > + tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, \ > + tm.tm_hour, tm.tm_min, tm.tm_sec, ts.tv_nsec); \ > + } while (0); > + > +static void print_active_blockers_locked(void) > +{ > + struct suspend_blocker *blocker; > + > + list_for_each_entry(blocker, &active_blockers, link) > + pr_info("active suspend blocker %s\n", blocker->name); > +} > + > +/** > + * suspend_is_blocked() - Check if suspend should be blocked > + * > + * suspend_is_blocked can be used by generic power management code to abort > + * suspend. > + * > + * To preserve backward compatibility suspend_is_blocked returns 0 unless it > + * is called during suspend initiated from the suspend_block code. > + */ > +bool suspend_is_blocked(void) > +{ > + if (!enable_suspend_blockers) > + return 0; > + return !list_empty(&active_blockers); > +} > + > +static void suspend_worker(struct work_struct *work) > +{ > + int ret; > + int entry_event_num; > + > + enable_suspend_blockers = true; > + while (!suspend_is_blocked()) { > + entry_event_num = current_event_num; > + > + if (debug_mask & DEBUG_SUSPEND) > + pr_info("suspend: enter suspend\n"); > + > + ret = pm_suspend(requested_suspend_state); > + > + if (debug_mask & DEBUG_EXIT_SUSPEND) > + pr_info_time("suspend: exit suspend, ret = %d ", ret); > + > + if (current_event_num == entry_event_num) > + pr_info("suspend: pm_suspend returned with no event\n"); > + } > + enable_suspend_blockers = false; > +} > +static DECLARE_WORK(suspend_work, suspend_worker); > + > +/** > + * suspend_blocker_init() - Initialize a suspend blocker > + * @blocker: The suspend blocker to initialize. > + * @name: The name of the suspend blocker to show in debug messages. > + * > + * The suspend blocker struct and name must not be freed before calling > + * suspend_blocker_destroy. > + */ > +void suspend_blocker_init(struct suspend_blocker *blocker, const char *name) > +{ > + unsigned long irqflags = 0; > + > + WARN_ON(!name); > + > + if (debug_mask & DEBUG_SUSPEND_BLOCKER) > + pr_info("suspend_blocker_init name=%s\n", name); > + > + blocker->name = name; > + blocker->flags = SB_INITIALIZED; > + INIT_LIST_HEAD(&blocker->link); > + > + spin_lock_irqsave(&list_lock, irqflags); > + list_add(&blocker->link, &inactive_blockers); > + spin_unlock_irqrestore(&list_lock, irqflags); > +} > +EXPORT_SYMBOL(suspend_blocker_init); > + > +/** > + * suspend_blocker_destroy() - Destroy a suspend blocker > + * @blocker: The suspend blocker to destroy. > + */ > +void suspend_blocker_destroy(struct suspend_blocker *blocker) > +{ > + unsigned long irqflags; > + if (WARN_ON(!(blocker->flags & SB_INITIALIZED))) > + return; > + > + if (debug_mask & DEBUG_SUSPEND_BLOCKER) > + pr_info("suspend_blocker_destroy name=%s\n", blocker->name); > + > + spin_lock_irqsave(&list_lock, irqflags); > + blocker->flags &= ~SB_INITIALIZED; > + list_del(&blocker->link); > + if ((blocker->flags & SB_ACTIVE) && list_empty(&active_blockers)) > + queue_work(pm_wq, &suspend_work); > + spin_unlock_irqrestore(&list_lock, irqflags); > +} > +EXPORT_SYMBOL(suspend_blocker_destroy); > + > +/** > + * suspend_block() - Block suspend > + * @blocker: The suspend blocker to use > + * > + * It is safe to call this function from interrupt context. > + */ > +void suspend_block(struct suspend_blocker *blocker) > +{ > + unsigned long irqflags; > + > + if (WARN_ON(!(blocker->flags & SB_INITIALIZED))) > + return; > + > + spin_lock_irqsave(&list_lock, irqflags); > + > + if (debug_mask & DEBUG_SUSPEND_BLOCKER) > + pr_info("suspend_block: %s\n", blocker->name); > + > + blocker->flags |= SB_ACTIVE; > + list_move(&blocker->link, &active_blockers); > + current_event_num++; > + > + spin_unlock_irqrestore(&list_lock, irqflags); > +} > +EXPORT_SYMBOL(suspend_block); > + > +/** > + * suspend_unblock() - Unblock suspend > + * @blocker: The suspend blocker to unblock. > + * > + * If no other suspend blockers block suspend, the system will suspend. > + * > + * It is safe to call this function from interrupt context. > + */ > +void suspend_unblock(struct suspend_blocker *blocker) > +{ > + unsigned long irqflags; > + > + if (WARN_ON(!(blocker->flags & SB_INITIALIZED))) > + return; > + > + spin_lock_irqsave(&list_lock, irqflags); > + > + if (debug_mask & DEBUG_SUSPEND_BLOCKER) > + pr_info("suspend_unblock: %s\n", blocker->name); > + > + list_move(&blocker->link, &inactive_blockers); > + > + if ((blocker->flags & SB_ACTIVE) && list_empty(&active_blockers)) > + queue_work(pm_wq, &suspend_work); > + blocker->flags &= ~(SB_ACTIVE); > + if (blocker == &main_suspend_blocker) { > + if (debug_mask & DEBUG_SUSPEND) > + print_active_blockers_locked(); > + } > + spin_unlock_irqrestore(&list_lock, irqflags); > +} > +EXPORT_SYMBOL(suspend_unblock); > + > +/** > + * suspend_blocker_is_active() - Test if a suspend blocker is blocking suspend > + * @blocker: The suspend blocker to check. > + * > + * Returns true if the suspend_blocker is currently active. > + */ > +bool suspend_blocker_is_active(struct suspend_blocker *blocker) > +{ > + WARN_ON(!(blocker->flags & SB_INITIALIZED)); > + > + return !!(blocker->flags & SB_ACTIVE); > +} > +EXPORT_SYMBOL(suspend_blocker_is_active); > + > +bool request_suspend_valid_state(suspend_state_t state) > +{ > + return (state == PM_SUSPEND_ON) || valid_state(state); > +} > + > +int request_suspend_state(suspend_state_t state) > +{ > + unsigned long irqflags; > + > + if (!request_suspend_valid_state(state)) > + return -ENODEV; > + > + spin_lock_irqsave(&state_lock, irqflags); > + > + if (debug_mask & DEBUG_USER_STATE) > + pr_info_time("request_suspend_state: %s (%d->%d) at %lld ", > + state != PM_SUSPEND_ON ? "sleep" : "wakeup", > + requested_suspend_state, state, > + ktime_to_ns(ktime_get())); > + > + requested_suspend_state = state; > + if (state == PM_SUSPEND_ON) > + suspend_block(&main_suspend_blocker); > + else > + suspend_unblock(&main_suspend_blocker); > + spin_unlock_irqrestore(&state_lock, irqflags); > + return 0; > +} > + > +void __init suspend_block_init(void) > +{ > + suspend_blocker_init(&main_suspend_blocker, "main"); > + suspend_block(&main_suspend_blocker); > +} -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html