[PATCH 6/9] PM: Add a switch for disabling/enabling asynchronous suspend/resume

Rafael J. Wysocki
2009-09-09T23:38:25Z

Add sysfs attribute kernel/power/pm_async allowing the user space to
disable and enable async suspend/resume of devices.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
drivers/base/power/main.c | 13 +++++++------
drivers/base/power/power.h | 6 +++---
kernel/power/main.c | 31 ++++++++++++++++++++++++++++++-
3 files changed, 40 insertions(+), 10 deletions(-)

Index: linux-2.6/kernel/power/main.c
===================================================================
--- linux-2.6.orig/kernel/power/main.c
+++ linux-2.6/kernel/power/main.c
@@ -44,6 +44,32 @@ int pm_notifier_call_chain(unsigned long
== NOTIFY_BAD) ? -EINVAL : 0;
}

+/* If set, devices may be suspended and resumed asynchronously. */
+int pm_async_enabled = 1;
+
+static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%d\n", pm_async_enabled);
+}
+
+static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr,
+ const char *buf, size_t n)
+{
+ unsigned long val;
+
+ if (strict_strtoul(buf, 10, &val))
+ return -EINVAL;
+
+ if (val > 1)
+ return -EINVAL;
+
+ pm_async_enabled = val;
+ return n;
+}
+
+power_attr(pm_async);
+
#ifdef CONFIG_PM_DEBUG
int pm_test_level = TEST_NONE;

@@ -208,9 +234,12 @@ static struct attribute * g[] = {
#ifdef CONFIG_PM_TRACE
&pm_trace_attr.attr,
#endif
-#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_PM_DEBUG)
+#ifdef CONFIG_PM_SLEEP
+ &pm_async_attr.attr,
+#ifdef CONFIG_PM_DEBUG
&pm_test_attr.attr,
#endif
+#endif
NULL,
};

Index: linux-2.6/drivers/base/power/main.c
===================================================================
--- linux-2.6.orig/drivers/base/power/main.c
+++ linux-2.6/drivers/base/power/main.c
@@ -235,7 +235,7 @@ static int device_pm_wait_fn(struct devi
*/
static void device_pm_wait_for_masters(struct device *slave)
{
- if (!pm_trace_enabled)
+ if (pm_async_enabled && !pm_trace_enabled)
device_for_each_master(slave, slave, device_pm_wait_fn);
}

@@ -245,7 +245,8 @@ static void device_pm_wait_for_masters(s
*/
static void device_pm_wait_for_slaves(struct device *master)
{
- device_for_each_slave(master, master, device_pm_wait_fn);
+ if (pm_async_enabled)
+ device_for_each_slave(master, master, device_pm_wait_fn);
}

/**
@@ -560,7 +561,7 @@ static int device_resume_noirq(struct de
if (pm_op_started(dev))
return 0;

- if (dev->power.async_suspend && !pm_trace_enabled) {
+ if (pm_async_enabled && !pm_trace_enabled && dev->power.async_suspend) {
async_schedule(async_resume_noirq, dev);
return 0;
}
@@ -719,7 +720,7 @@ static int device_resume(struct device *
if (pm_op_started(dev))
return 0;

- if (dev->power.async_suspend && !pm_trace_enabled) {
+ if (pm_async_enabled && !pm_trace_enabled && dev->power.async_suspend) {
get_device(dev);
async_schedule(async_resume, dev);
return 0;
@@ -965,7 +966,7 @@ static int device_suspend_noirq(struct d
if (pm_op_started(dev))
return 0;

- if (dev->power.async_suspend) {
+ if (pm_async_enabled && dev->power.async_suspend) {
async_schedule(async_suspend_noirq, dev);
return 0;
}
@@ -1139,7 +1140,7 @@ static int device_suspend(struct device
if (pm_op_started(dev))
return 0;

- if (dev->power.async_suspend) {
+ if (pm_async_enabled && dev->power.async_suspend) {
get_device(dev);
async_schedule(async_suspend, dev);
return 0;
Index: linux-2.6/drivers/base/power/power.h
===================================================================
--- linux-2.6.orig/drivers/base/power/power.h
+++ linux-2.6/drivers/base/power/power.h
@@ -16,10 +16,10 @@ static inline void pm_runtime_remove(str

#ifdef CONFIG_PM_SLEEP

-/*
- * main.c
- */
+/* kernel/power/main.c */
+extern int pm_async_enabled;

+/* drivers/base/power/main.c */
extern struct list_head dpm_list; /* The active device list */

static inline struct device *to_device(struct list_head *entry)