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authorRafael J. Wysocki <rjw@sisk.pl>2012-04-29 22:53:22 +0200
committerRafael J. Wysocki <rjw@sisk.pl>2012-05-01 21:25:38 +0200
commit7483b4a4d9abf9dcf1ffe6e805ead2847ec3264e (patch)
treed03af746dc3be6480580ec569e0c2d708031f0bd /kernel
parent6791e36c4a40e8930e08669e60077eea6770c429 (diff)
downloadlinux-7483b4a4d9abf9dcf1ffe6e805ead2847ec3264e.tar.bz2
PM / Sleep: Implement opportunistic sleep, v2
Introduce a mechanism by which the kernel can trigger global transitions to a sleep state chosen by user space if there are no active wakeup sources. It consists of a new sysfs attribute, /sys/power/autosleep, that can be written one of the strings returned by reads from /sys/power/state, an ordered workqueue and a work item carrying out the "suspend" operations. If a string representing the system's sleep state is written to /sys/power/autosleep, the work item triggering transitions to that state is queued up and it requeues itself after every execution until user space writes "off" to /sys/power/autosleep. That work item enables the detection of wakeup events using the functions already defined in drivers/base/power/wakeup.c (with one small modification) and calls either pm_suspend(), or hibernate() to put the system into a sleep state. If a wakeup event is reported while the transition is in progress, it will abort the transition and the "system suspend" work item will be queued up again. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/power/Kconfig8
-rw-r--r--kernel/power/Makefile1
-rw-r--r--kernel/power/autosleep.c123
-rw-r--r--kernel/power/main.c119
-rw-r--r--kernel/power/power.h18
5 files changed, 250 insertions, 19 deletions
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index deb5461e3216..67947083f842 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -103,6 +103,14 @@ config PM_SLEEP_SMP
select HOTPLUG
select HOTPLUG_CPU
+config PM_AUTOSLEEP
+ bool "Opportunistic sleep"
+ depends on PM_SLEEP
+ default n
+ ---help---
+ Allow the kernel to trigger a system transition into a global sleep
+ state automatically whenever there are no active wakeup sources.
+
config PM_RUNTIME
bool "Run-time PM core functionality"
depends on !IA64_HP_SIM
diff --git a/kernel/power/Makefile b/kernel/power/Makefile
index 66d808ec5252..010b2f7e148c 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -9,5 +9,6 @@ obj-$(CONFIG_SUSPEND) += suspend.o
obj-$(CONFIG_PM_TEST_SUSPEND) += suspend_test.o
obj-$(CONFIG_HIBERNATION) += hibernate.o snapshot.o swap.o user.o \
block_io.o
+obj-$(CONFIG_PM_AUTOSLEEP) += autosleep.o
obj-$(CONFIG_MAGIC_SYSRQ) += poweroff.o
diff --git a/kernel/power/autosleep.c b/kernel/power/autosleep.c
new file mode 100644
index 000000000000..42348e3589d3
--- /dev/null
+++ b/kernel/power/autosleep.c
@@ -0,0 +1,123 @@
+/*
+ * kernel/power/autosleep.c
+ *
+ * Opportunistic sleep support.
+ *
+ * Copyright (C) 2012 Rafael J. Wysocki <rjw@sisk.pl>
+ */
+
+#include <linux/device.h>
+#include <linux/mutex.h>
+#include <linux/pm_wakeup.h>
+
+#include "power.h"
+
+static suspend_state_t autosleep_state;
+static struct workqueue_struct *autosleep_wq;
+/*
+ * Note: it is only safe to mutex_lock(&autosleep_lock) if a wakeup_source
+ * is active, otherwise a deadlock with try_to_suspend() is possible.
+ * Alternatively mutex_lock_interruptible() can be used. This will then fail
+ * if an auto_sleep cycle tries to freeze processes.
+ */
+static DEFINE_MUTEX(autosleep_lock);
+static struct wakeup_source *autosleep_ws;
+
+static void try_to_suspend(struct work_struct *work)
+{
+ unsigned int initial_count, final_count;
+
+ if (!pm_get_wakeup_count(&initial_count, true))
+ goto out;
+
+ mutex_lock(&autosleep_lock);
+
+ if (!pm_save_wakeup_count(initial_count)) {
+ mutex_unlock(&autosleep_lock);
+ goto out;
+ }
+
+ if (autosleep_state == PM_SUSPEND_ON) {
+ mutex_unlock(&autosleep_lock);
+ return;
+ }
+ if (autosleep_state >= PM_SUSPEND_MAX)
+ hibernate();
+ else
+ pm_suspend(autosleep_state);
+
+ mutex_unlock(&autosleep_lock);
+
+ if (!pm_get_wakeup_count(&final_count, false))
+ goto out;
+
+ /*
+ * If the wakeup occured for an unknown reason, wait to prevent the
+ * system from trying to suspend and waking up in a tight loop.
+ */
+ if (final_count == initial_count)
+ schedule_timeout_uninterruptible(HZ / 2);
+
+ out:
+ queue_up_suspend_work();
+}
+
+static DECLARE_WORK(suspend_work, try_to_suspend);
+
+void queue_up_suspend_work(void)
+{
+ if (!work_pending(&suspend_work) && autosleep_state > PM_SUSPEND_ON)
+ queue_work(autosleep_wq, &suspend_work);
+}
+
+suspend_state_t pm_autosleep_state(void)
+{
+ return autosleep_state;
+}
+
+int pm_autosleep_lock(void)
+{
+ return mutex_lock_interruptible(&autosleep_lock);
+}
+
+void pm_autosleep_unlock(void)
+{
+ mutex_unlock(&autosleep_lock);
+}
+
+int pm_autosleep_set_state(suspend_state_t state)
+{
+
+#ifndef CONFIG_HIBERNATION
+ if (state >= PM_SUSPEND_MAX)
+ return -EINVAL;
+#endif
+
+ __pm_stay_awake(autosleep_ws);
+
+ mutex_lock(&autosleep_lock);
+
+ autosleep_state = state;
+
+ __pm_relax(autosleep_ws);
+
+ if (state > PM_SUSPEND_ON)
+ queue_up_suspend_work();
+
+ mutex_unlock(&autosleep_lock);
+ return 0;
+}
+
+int __init pm_autosleep_init(void)
+{
+ autosleep_ws = wakeup_source_register("autosleep");
+ if (!autosleep_ws)
+ return -ENOMEM;
+
+ autosleep_wq = alloc_ordered_workqueue("autosleep", 0);
+ if (autosleep_wq)
+ return 0;
+
+ wakeup_source_unregister(autosleep_ws);
+ return -ENOMEM;
+}
diff --git a/kernel/power/main.c b/kernel/power/main.c
index 1c12581f1c62..ba6a5645952d 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -269,8 +269,7 @@ static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
return (s - buf);
}
-static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
- const char *buf, size_t n)
+static suspend_state_t decode_state(const char *buf, size_t n)
{
#ifdef CONFIG_SUSPEND
suspend_state_t state = PM_SUSPEND_STANDBY;
@@ -278,27 +277,48 @@ static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
#endif
char *p;
int len;
- int error = -EINVAL;
p = memchr(buf, '\n', n);
len = p ? p - buf : n;
- /* First, check if we are requested to hibernate */
- if (len == 4 && !strncmp(buf, "disk", len)) {
- error = hibernate();
- goto Exit;
- }
+ /* Check hibernation first. */
+ if (len == 4 && !strncmp(buf, "disk", len))
+ return PM_SUSPEND_MAX;
#ifdef CONFIG_SUSPEND
- for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
- if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
- error = pm_suspend(state);
- break;
- }
- }
+ for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++)
+ if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
+ return state;
#endif
- Exit:
+ return PM_SUSPEND_ON;
+}
+
+static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
+ const char *buf, size_t n)
+{
+ suspend_state_t state;
+ int error;
+
+ error = pm_autosleep_lock();
+ if (error)
+ return error;
+
+ if (pm_autosleep_state() > PM_SUSPEND_ON) {
+ error = -EBUSY;
+ goto out;
+ }
+
+ state = decode_state(buf, n);
+ if (state < PM_SUSPEND_MAX)
+ error = pm_suspend(state);
+ else if (state == PM_SUSPEND_MAX)
+ error = hibernate();
+ else
+ error = -EINVAL;
+
+ out:
+ pm_autosleep_unlock();
return error ? error : n;
}
@@ -339,7 +359,8 @@ static ssize_t wakeup_count_show(struct kobject *kobj,
{
unsigned int val;
- return pm_get_wakeup_count(&val) ? sprintf(buf, "%u\n", val) : -EINTR;
+ return pm_get_wakeup_count(&val, true) ?
+ sprintf(buf, "%u\n", val) : -EINTR;
}
static ssize_t wakeup_count_store(struct kobject *kobj,
@@ -347,15 +368,69 @@ static ssize_t wakeup_count_store(struct kobject *kobj,
const char *buf, size_t n)
{
unsigned int val;
+ int error;
+
+ error = pm_autosleep_lock();
+ if (error)
+ return error;
+ if (pm_autosleep_state() > PM_SUSPEND_ON) {
+ error = -EBUSY;
+ goto out;
+ }
+
+ error = -EINVAL;
if (sscanf(buf, "%u", &val) == 1) {
if (pm_save_wakeup_count(val))
- return n;
+ error = n;
}
- return -EINVAL;
+
+ out:
+ pm_autosleep_unlock();
+ return error;
}
power_attr(wakeup_count);
+
+#ifdef CONFIG_PM_AUTOSLEEP
+static ssize_t autosleep_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ suspend_state_t state = pm_autosleep_state();
+
+ if (state == PM_SUSPEND_ON)
+ return sprintf(buf, "off\n");
+
+#ifdef CONFIG_SUSPEND
+ if (state < PM_SUSPEND_MAX)
+ return sprintf(buf, "%s\n", valid_state(state) ?
+ pm_states[state] : "error");
+#endif
+#ifdef CONFIG_HIBERNATION
+ return sprintf(buf, "disk\n");
+#else
+ return sprintf(buf, "error");
+#endif
+}
+
+static ssize_t autosleep_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t n)
+{
+ suspend_state_t state = decode_state(buf, n);
+ int error;
+
+ if (state == PM_SUSPEND_ON
+ && !(strncmp(buf, "off", 3) && strncmp(buf, "off\n", 4)))
+ return -EINVAL;
+
+ error = pm_autosleep_set_state(state);
+ return error ? error : n;
+}
+
+power_attr(autosleep);
+#endif /* CONFIG_PM_AUTOSLEEP */
#endif /* CONFIG_PM_SLEEP */
#ifdef CONFIG_PM_TRACE
@@ -409,6 +484,9 @@ static struct attribute * g[] = {
#ifdef CONFIG_PM_SLEEP
&pm_async_attr.attr,
&wakeup_count_attr.attr,
+#ifdef CONFIG_PM_AUTOSLEEP
+ &autosleep_attr.attr,
+#endif
#ifdef CONFIG_PM_DEBUG
&pm_test_attr.attr,
#endif
@@ -444,7 +522,10 @@ static int __init pm_init(void)
power_kobj = kobject_create_and_add("power", NULL);
if (!power_kobj)
return -ENOMEM;
- return sysfs_create_group(power_kobj, &attr_group);
+ error = sysfs_create_group(power_kobj, &attr_group);
+ if (error)
+ return error;
+ return pm_autosleep_init();
}
core_initcall(pm_init);
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 98f3622d7407..4cf80fa115d9 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -264,3 +264,21 @@ static inline void suspend_thaw_processes(void)
{
}
#endif
+
+#ifdef CONFIG_PM_AUTOSLEEP
+
+/* kernel/power/autosleep.c */
+extern int pm_autosleep_init(void);
+extern int pm_autosleep_lock(void);
+extern void pm_autosleep_unlock(void);
+extern suspend_state_t pm_autosleep_state(void);
+extern int pm_autosleep_set_state(suspend_state_t state);
+
+#else /* !CONFIG_PM_AUTOSLEEP */
+
+static inline int pm_autosleep_init(void) { return 0; }
+static inline int pm_autosleep_lock(void) { return 0; }
+static inline void pm_autosleep_unlock(void) {}
+static inline suspend_state_t pm_autosleep_state(void) { return PM_SUSPEND_ON; }
+
+#endif /* !CONFIG_PM_AUTOSLEEP */