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authorRafael J. Wysocki <rjw@sisk.pl>2009-08-18 23:38:32 +0200
committerRafael J. Wysocki <rjw@sisk.pl>2009-08-23 00:04:44 +0200
commit5e928f77a09a07f9dd595bb8a489965d69a83458 (patch)
treeef53ec90fa3214fd22e36b07c11c06b09e373d8d /kernel
parent8400146d0dc03590bba051399e4bb7e1cbf1c010 (diff)
PM: Introduce core framework for run-time PM of I/O devices (rev. 17)
Introduce a core framework for run-time power management of I/O devices. Add device run-time PM fields to 'struct dev_pm_info' and device run-time PM callbacks to 'struct dev_pm_ops'. Introduce a run-time PM workqueue and define some device run-time PM helper functions at the core level. Document all these things. Special thanks to Alan Stern for his help with the design and multiple detailed reviews of the pereceding versions of this patch and to Magnus Damm for testing feedback. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Magnus Damm <damm@igel.co.jp>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/power/Kconfig14
-rw-r--r--kernel/power/main.c17
2 files changed, 31 insertions, 0 deletions
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 72067cbdb37f..91e09d3b2eb2 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -208,3 +208,17 @@ config APM_EMULATION
random kernel OOPSes or reboots that don't seem to be related to
anything, try disabling/enabling this option (or disabling/enabling
APM in your BIOS).
+
+config PM_RUNTIME
+ bool "Run-time PM core functionality"
+ depends on PM
+ ---help---
+ Enable functionality allowing I/O devices to be put into energy-saving
+ (low power) states at run time (or autosuspended) after a specified
+ period of inactivity and woken up in response to a hardware-generated
+ wake-up event or a driver's request.
+
+ Hardware support is generally required for this functionality to work
+ and the bus type drivers of the buses the devices are on are
+ responsible for the actual handling of the autosuspend requests and
+ wake-up events.
diff --git a/kernel/power/main.c b/kernel/power/main.c
index f710e36930cc..347d2cc88cd0 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -11,6 +11,7 @@
#include <linux/kobject.h>
#include <linux/string.h>
#include <linux/resume-trace.h>
+#include <linux/workqueue.h>
#include "power.h"
@@ -217,8 +218,24 @@ static struct attribute_group attr_group = {
.attrs = g,
};
+#ifdef CONFIG_PM_RUNTIME
+struct workqueue_struct *pm_wq;
+
+static int __init pm_start_workqueue(void)
+{
+ pm_wq = create_freezeable_workqueue("pm");
+
+ return pm_wq ? 0 : -ENOMEM;
+}
+#else
+static inline int pm_start_workqueue(void) { return 0; }
+#endif
+
static int __init pm_init(void)
{
+ int error = pm_start_workqueue();
+ if (error)
+ return error;
power_kobj = kobject_create_and_add("power", NULL);
if (!power_kobj)
return -ENOMEM;