On Wednesday 10 June 2009, Rafael J. Wysocki wrote:
> On Tuesday 09 June 2009, Alan Stern wrote:
> > On Mon, 8 Jun 2009, Rafael J. Wysocki wrote:
> >
> > > > Use of the RPM_UNKNOWN state isn't good. A bus may have valid reasons
> > > > of its own for not carrying out an autosuspend. When this happens the
> > > > device's state isn't unknown.
> > >
> > > I'm not sure what you mean exactly.
> > >
> > > If ->autosuspend() fails, the device power state may be known, but the core
> > > can't be sure if the device is active. This information is available to the
> > > driver and/or the bus type, which should change the status to whatever is
> > > appropriate.
> >
> > But no matter what the driver or bus type sets the state to, your
> > pm_autosuspend() will change it to one of RPM_UNKNOWN or RPM_SUSPENDED.
> > Neither might be right.
>
> The idea is that if ->autosuspend() or ->autoresume() returns an error code,
> this is a situation the PM core cannot recover from by itself, so it shouldn't
> pretend it knows what's happened. Instead, it marks the device as "I don't
> know if it is safe to touch this" and won't handle it until the device driver
> or bus type clears the status.
>
> > > The name of this constant may be confusing, but I didn't have any better ideas.
> >
> > It's not clear what RPM_ACTIVE, RPM_IDLE, and RPM_SUSPENDED are
> > supposed to mean; this should be documented in the code. Also, why
> > isn't there RPM_RESUMING?
>
> Yes, there should be. In fact it's in the current version of the patch, which
> is appended. Also, there's a comment explaining the meaning of the RPM_*
> constants in pm.h .
>
> > By the way, a legitimate reason for aborting an autosuspend is if the
> > device's driver requires remote wakeup to be enabled during suspend but
> > the user has disabled it.
>
> Do you mean the user has disabled the remote wakeup?
>
> > > > The scheme doesn't include any mechanism for communicating runtime
> > > > power information up the device tree. When a device is autosuspended,
> > > > its parent's driver should be told so that the driver can consider
> > > > autosuspending the parent.
> > >
> > > I thought the bus type's ->autosuspend() callback could take care of this.
> >
> > Shouldn't this happen after the device's state has changed to
> > RPM_SUSPENDED? That's not until after the callback returns.
>
> OK, I tried to address the issue of parent suspend/resume in the new
> version of the patch below (I'm not sure if I did the nesting of spinlocks in
> pm_request_resume() correctly).
>
> > > > There should be a sysfs interface (like the one in USB) to allow
> > > > userspace to prevent a device from being autosuspended -- and perhaps
> > > > also to force it to be suspended.
> > >
> > > To prevent a device from being suspended - yes. To force it to stay suspended
> > > - I'm not sure.
> >
> > I'm not sure either. Oliver Neukum requested it originally and it has
> > been useful for debugging, but I haven't seen many places where it
> > would come in useful in practice.
>
> The problem with it is that the user space may not know if it is safe to keep
> a device suspended and if it is not, the kernel will have to ignore the setting
> anyway, so I'm not sure what's the point (except for debugging).
>
> > > > What about devices that have more than two runtime power states? For
> > > > example, you can't squeeze PCI's {D0,D1,D2,D3hot} range into {running,
> > > > suspended}.
> > >
> > > That has to be bus type-specific.
> > >
> > > In the case of PCI all of the low power states (D1-D3) are in fact substates of
> > > "suspended", because we generally need to quiesce the device before putting
> > > it into any of these states.
> > >
> > > I'm not sure if we can introduce more "levels of suspension", so to speak, at
> > > the core level, but in any case we can easily distinguish between "device
> > > quiesced and in a low power state" and "device fully active".
> > >
> > > So, in this picture the device is "suspended" from the core's point of view
> > > once it's bus type's ->autosuspend() callback has been successfully executed.
> >
> > This too should be documented in the code. Or in a Documentation file.
>
> OK
>
> I tried to address your comments and the Oliver's comments too in the new
> version of the patch below. Please have a look and tell me what you think.
Argh, I forgot about some important things.
First, there are devices with no parent (actually, it would be much easier if
they had a default dummy parent, but that's a separate issue).
Second, the parent has to be taken into account in the asynchronous resume
path too (which BTW is more complicated).
Finally, I decided to follow the Oliver's suggestion that some error codes returned
by ->autosuspend() and ->autoresume() may be regarded as "go back to the
previous state" information. I chose to use -EAGAIN and -EBUSY for this
purpose.
Updated patch follows, sorry for the confusion.
Best,
Rafael
---
drivers/base/power/Makefile | 1
drivers/base/power/main.c | 2
drivers/base/power/runtime.c | 393 +++++++++++++++++++++++++++++++++++++++++++
include/linux/pm.h | 78 ++++++++
include/linux/pm_runtime.h | 50 +++++
kernel/power/Kconfig | 14 +
kernel/power/main.c | 17 +
7 files changed, 553 insertions(+), 2 deletions(-)
Index: linux-2.6/kernel/power/Kconfig
===================================================================
--- linux-2.6.orig/kernel/power/Kconfig
+++ linux-2.6/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
+ responsibile for the actual handling of the autosuspend requests and
+ wake-up events.
Index: linux-2.6/kernel/power/main.c
===================================================================
--- linux-2.6.orig/kernel/power/main.c
+++ linux-2.6/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;
Index: linux-2.6/include/linux/pm.h
===================================================================
--- linux-2.6.orig/include/linux/pm.h
+++ linux-2.6/include/linux/pm.h
@@ -22,6 +22,9 @@
#define _LINUX_PM_H
#include <linux/list.h>
+#include <linux/workqueue.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
/*
* Callbacks for platform drivers to implement.
@@ -165,6 +168,15 @@ typedef struct pm_message {
* It is allowed to unregister devices while the above callbacks are being
* executed. However, it is not allowed to unregister a device from within any
* of its own callbacks.
+ *
+ * There also are two callbacks related to run-time power management of devices:
+ *
+ * @autosuspend: Save the device registers and put it into an energy-saving (low
+ * power) state at run-time, enable wake-up events as appropriate.
+ *
+ * @autoresume: Put the device into the full power state and restore its
+ * registers (if applicable) at run time, in response to a wake-up event
+ * generated by hardware or at a request of software.
*/
struct dev_pm_ops {
@@ -182,6 +194,10 @@ struct dev_pm_ops {
int (*thaw_noirq)(struct device *dev);
int (*poweroff_noirq)(struct device *dev);
int (*restore_noirq)(struct device *dev);
+#ifdef CONFIG_PM_RUNTIME
+ int (*autosuspend)(struct device *dev);
+ int (*autoresume)(struct device *dev);
+#endif
};
/**
@@ -315,14 +331,72 @@ enum dpm_state {
DPM_OFF_IRQ,
};
+/**
+ * Device run-time power management state.
+ *
+ * These state labels are used internally by the PM core to indicate the current
+ * status of a device with respect to the PM core operations. They do not
+ * reflect the actual power state of the device or its status as seen by the
+ * driver.
+ *
+ * RPM_ACTIVE Device is fully operational, no run-time PM requests are
+ * pending for it.
+ *
+ * RPM_IDLE It has been requested that the device be suspended.
+ * Suspend request has been put into the run-time PM
+ * workqueue and it's pending execution.
+ *
+ * RPM_SUSPENDING Device bus type's ->autosuspend() callback is being
+ * executed.
+ *
+ * RPM_SUSPENDED Device bus type's ->autosuspend() callback has completed
+ * successfully. The device is regarded as suspended.
+ *
+ * RPM_WAKE It has been requested that the device be woken up.
+ * Resume request has been put into the run-time PM
+ * workqueue and it's pending execution.
+ *
+ * RPM_RESUMING Device bus type's ->autoresume() callback is being
+ * executed.
+ *
+ * RPM_ERROR Represents a condition from which the PM core cannot
+ * recover by itself. If the device's run-time PM status
+ * field has this value, all of the run-time PM operations
+ * carried out for the device by the core will fail, until
+ * the status field is changed to either RPM_ACTIVE or
+ * RPM_SUSPENDED (it is not valid to use the other values
+ * in such a situation) by the device's driver or bus type.
+ * This happens when the device bus type's ->autosuspend()
+ * or ->autoresume() callback returns error code other than
+ * -EAGAIN or -EBUSY.
+ */
+
+enum rpm_state {
+ RPM_ERROR = -1,
+ RPM_ACTIVE,
+ RPM_IDLE,
+ RPM_SUSPENDING,
+ RPM_SUSPENDED,
+ RPM_WAKE,
+ RPM_RESUMING,
+};
+
struct dev_pm_info {
pm_message_t power_state;
- unsigned can_wakeup:1;
- unsigned should_wakeup:1;
+ unsigned int can_wakeup:1;
+ unsigned int should_wakeup:1;
enum dpm_state status; /* Owned by the PM core */
#ifdef CONFIG_PM_SLEEP
struct list_head entry;
#endif
+#ifdef CONFIG_PM_RUNTIME
+ struct delayed_work suspend_work;
+ unsigned int suspend_aborted:1;
+ struct work_struct resume_work;
+ struct completion work_done;
+ enum rpm_state runtime_status;
+ spinlock_t lock;
+#endif
};
/*
Index: linux-2.6/drivers/base/power/Makefile
===================================================================
--- linux-2.6.orig/drivers/base/power/Makefile
+++ linux-2.6/drivers/base/power/Makefile
@@ -1,5 +1,6 @@
obj-$(CONFIG_PM) += sysfs.o
obj-$(CONFIG_PM_SLEEP) += main.o
+obj-$(CONFIG_PM_RUNTIME) += runtime.o
obj-$(CONFIG_PM_TRACE_RTC) += trace.o
ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
Index: linux-2.6/drivers/base/power/runtime.c
===================================================================
--- /dev/null
+++ linux-2.6/drivers/base/power/runtime.c
@@ -0,0 +1,393 @@
+/*
+ * drivers/base/power/runtime.c - Helper functions for device run-time PM
+ *
+ * Copyright (c) 2009 Rafael J. Wysocki <rjw@xxxxxxx>, Novell Inc.
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/pm_runtime.h>
+
+/**
+ * pm_runtime_reset - Clear all of the device run-time PM flags.
+ * @dev: Device object to clear the flags for.
+ */
+static void pm_runtime_reset(struct device *dev)
+{
+ dev->power.suspend_aborted = false;
+ dev->power.runtime_status = RPM_ACTIVE;
+}
+
+/**
+ * pm_device_suspended - Check if given device has been suspended at run time.
+ * @dev: Device to check.
+ * @data: Ignored.
+ *
+ * Returns 0 if the device has been suspended or -EBUSY otherwise.
+ */
+static int pm_device_suspended(struct device *dev, void *data)
+{
+ int ret;
+
+ spin_lock(&dev->power.lock);
+
+ ret = dev->power.runtime_status == RPM_SUSPENDED ? 0 : -EBUSY;
+
+ spin_unlock(&dev->power.lock);
+
+ return ret;
+}
+
+/**
+ * pm_check_children - Check if all children of a device have been suspended.
+ * @dev: Device to check.
+ *
+ * Returns 0 if all children of the device have been suspended or -EBUSY
+ * otherwise.
+ */
+static int pm_check_children(struct device *dev)
+{
+ return device_for_each_child(dev, NULL, pm_device_suspended);
+}
+
+/**
+ * pm_autosuspend - Run autosuspend callback of given device object's bus type.
+ * @work: Work structure used for scheduling the execution of this function.
+ *
+ * Use @work to get the device object the suspend has been scheduled for,
+ * check if the suspend request hasn't been cancelled and run the
+ * ->autosuspend() callback from the device's bus type driver. Update the
+ * run-time PM flags in the device object to reflect the current status of the
+ * device.
+ */
+static void pm_autosuspend(struct work_struct *work)
+{
+ struct delayed_work *dw = to_delayed_work(work);
+ struct device *dev = suspend_work_to_device(dw);
+ int error = 0;
+
+ spin_lock(&dev->power.lock);
+
+ if (dev->power.suspend_aborted) {
+ dev->power.runtime_status = RPM_ACTIVE;
+ goto out;
+ } else if (dev->power.runtime_status != RPM_IDLE) {
+ goto out;
+ } else if (pm_check_children(dev)) {
+ /*
+ * We can only suspend the device if all of its children have
+ * been suspended.
+ */
+ goto out;
+ }
+
+ dev->power.runtime_status = RPM_SUSPENDING;
+ init_completion(&dev->power.work_done);
+
+ spin_unlock(&dev->power.lock);
+
+ if (dev && dev->bus && dev->bus->pm && dev->bus->pm->autosuspend)
+ error = dev->bus->pm->autosuspend(dev);
+
+ spin_lock(&dev->power.lock);
+
+ switch (error) {
+ case 0:
+ dev->power.runtime_status = RPM_SUSPENDED;
+ break;
+ case -EAGAIN:
+ case -EBUSY:
+ dev->power.runtime_status = RPM_ACTIVE;
+ break;
+ default:
+ dev->power.runtime_status = RPM_ERROR;
+ }
+ complete(&dev->power.work_done);
+
+ out:
+ spin_unlock(&dev->power.lock);
+}
+
+/**
+ * pm_request_suspend - Schedule run-time suspend of given device.
+ * @dev: Device to suspend.
+ * @delay: Time to wait before attempting to suspend the device.
+ */
+void pm_request_suspend(struct device *dev, unsigned long delay)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&dev->power.lock, flags);
+
+ if (dev->power.runtime_status != RPM_ACTIVE)
+ goto out;
+
+ dev->power.runtime_status = RPM_IDLE;
+ dev->power.suspend_aborted = false;
+ queue_delayed_work(pm_wq, &dev->power.suspend_work, delay);
+
+ out:
+ spin_unlock_irqrestore(&dev->power.lock, flags);
+}
+
+/**
+ * pm_cancel_suspend - Cancel a pending suspend request for given device.
+ * @dev: Device to cancel the suspend request for.
+ *
+ * Should be called under pm_lock_device() and only if we are sure that the
+ * ->autosuspend() callback hasn't started to yet.
+ */
+static void pm_cancel_suspend(struct device *dev)
+{
+ dev->power.suspend_aborted = true;
+ cancel_delayed_work(&dev->power.suspend_work);
+ dev->power.runtime_status = RPM_ACTIVE;
+}
+
+/**
+ * pm_autoresume - Run autoresume callback of given device object's bus type.
+ * @work: Work structure used for scheduling the execution of this function.
+ *
+ * Use @work to get the device object the resume has been scheduled for,
+ * check if the device is really suspended and run the ->autoresume() callback
+ * from the device's bus type driver. Update the run-time PM flags in the
+ * device object to reflect the current status of the device.
+ */
+static void pm_autoresume(struct work_struct *work)
+{
+ struct device *dev = resume_work_to_device(work);
+ int error = 0;
+
+ if (dev->parent)
+ spin_lock(&dev->parent->power.lock);
+ spin_lock(&dev->power.lock);
+
+ repeat:
+ if (dev->power.runtime_status != RPM_WAKE) {
+ if (dev->parent)
+ spin_unlock(&dev->parent->power.lock);
+ goto out;
+ } else if (dev->parent
+ && dev->parent->power.runtime_status != RPM_ACTIVE) {
+ if (dev->parent->power.runtime_status == RPM_RESUMING) {
+ spin_unlock(&dev->power.lock);
+ spin_unlock(&dev->parent->power.lock);
+
+ wait_for_completion(&dev->parent->power.work_done);
+
+ spin_lock(&dev->parent->power.lock);
+ spin_lock(&dev->power.lock);
+ }
+ if (dev->parent->power.runtime_status != RPM_ACTIVE) {
+ spin_unlock(&dev->parent->power.lock);
+ goto out;
+ }
+ goto repeat;
+ }
+
+ dev->power.runtime_status = RPM_RESUMING;
+ init_completion(&dev->power.work_done);
+
+ spin_unlock(&dev->power.lock);
+ if (dev->parent)
+ spin_unlock(&dev->parent->power.lock);
+
+ if (dev->bus && dev->bus->pm && dev->bus->pm->autoresume)
+ error = dev->bus->pm->autoresume(dev);
+
+ spin_lock(&dev->power.lock);
+
+ switch (error) {
+ case 0:
+ dev->power.runtime_status = RPM_ACTIVE;
+ break;
+ case -EAGAIN:
+ case -EBUSY:
+ dev->power.runtime_status = RPM_SUSPENDED;
+ break;
+ default:
+ dev->power.runtime_status = RPM_ERROR;
+ }
+ complete(&dev->power.work_done);
+
+ out:
+ spin_unlock(&dev->power.lock);
+}
+
+/**
+ * pm_request_resume - Schedule run-time resume of given device.
+ * @dev: Device to resume.
+ */
+void pm_request_resume(struct device *dev)
+{
+ unsigned long parent_flags = 0, flags;
+
+ repeat:
+ if (dev->parent)
+ spin_lock_irqsave(&dev->parent->power.lock, parent_flags);
+ spin_lock_irqsave(&dev->power.lock, flags);
+
+ if (dev->power.runtime_status == RPM_IDLE) {
+ /* Autosuspend request is pending, no need to resume. */
+ pm_cancel_suspend(dev);
+ goto out;
+ } else if (dev->power.runtime_status != RPM_SUSPENDING
+ && dev->power.runtime_status != RPM_SUSPENDED) {
+ goto out;
+ } else if (dev->parent
+ && (dev->parent->power.runtime_status == RPM_IDLE
+ || dev->parent->power.runtime_status == RPM_SUSPENDING
+ || dev->parent->power.runtime_status == RPM_SUSPENDED)) {
+ spin_unlock_irqrestore(&dev->power.lock, flags);
+ spin_unlock_irqrestore(&dev->parent->power.lock, parent_flags);
+
+ /* We have to resume the parent first. */
+ pm_request_resume(dev->parent);
+
+ goto repeat;
+ }
+
+ dev->power.runtime_status = RPM_WAKE;
+ queue_work(pm_wq, &dev->power.resume_work);
+
+ out:
+ spin_unlock_irqrestore(&dev->power.lock, flags);
+ if (dev->parent)
+ spin_unlock_irqrestore(&dev->parent->power.lock, parent_flags);
+}
+
+/**
+ * pm_resume_sync - Resume given device waiting for the operation to complete.
+ * @dev: Device to resume.
+ *
+ * Resume the device synchronously, waiting for the operation to complete. If
+ * autosuspend is in progress while this function is being run, wait for it to
+ * finish before resuming the device. If the autosuspend is scheduled, but it
+ * hasn't started yet, cancel it and we're done.
+ */
+int pm_resume_sync(struct device *dev)
+{
+ int error = 0;
+
+ spin_lock(&dev->power.lock);
+
+ if (dev->power.runtime_status == RPM_ACTIVE) {
+ goto out;
+ } if (dev->power.runtime_status == RPM_IDLE) {
+ /* ->autosuspend() hasn't started yet, no need to resume. */
+ pm_cancel_suspend(dev);
+ goto out;
+ }
+
+ if (dev->power.runtime_status == RPM_SUSPENDING) {
+ spin_unlock(&dev->power.lock);
+
+ /*
+ * The ->autosuspend() callback is being executed right now,
+ * wait for it to complete.
+ */
+ wait_for_completion(&dev->power.work_done);
+ } else if (dev->power.runtime_status == RPM_SUSPENDED && dev->parent) {
+ spin_unlock(&dev->power.lock);
+
+ /* The device's parent may also be suspended. Resume it. */
+ error = pm_resume_sync(dev->parent);
+ if (error)
+ return error;
+ } else {
+ spin_unlock(&dev->power.lock);
+ }
+
+ if (dev->parent)
+ spin_lock(&dev->parent->power.lock);
+ spin_lock(&dev->power.lock);
+
+ if (dev->power.runtime_status == RPM_RESUMING)
+ /* There's another resume running in parallel with us. */
+ error = -EAGAIN;
+ else if (dev->power.runtime_status != RPM_SUSPENDED)
+ error = -EINVAL;
+ if (error) {
+ if (dev->parent)
+ spin_unlock(&dev->parent->power.lock);
+ goto out;
+ }
+
+ dev->power.runtime_status = RPM_RESUMING;
+ init_completion(&dev->power.work_done);
+
+ spin_unlock(&dev->power.lock);
+ if (dev->parent)
+ spin_unlock(&dev->parent->power.lock);
+
+ if (dev->bus && dev->bus->pm && dev->bus->pm->autoresume)
+ error = dev->bus->pm->autoresume(dev);
+
+ spin_lock(&dev->power.lock);
+
+ switch (error) {
+ case 0:
+ dev->power.runtime_status = RPM_ACTIVE;
+ break;
+ case -EAGAIN:
+ case -EBUSY:
+ dev->power.runtime_status = RPM_SUSPENDED;
+ break;
+ default:
+ dev->power.runtime_status = RPM_ERROR;
+ }
+ complete(&dev->power.work_done);
+
+ out:
+ spin_unlock(&dev->power.lock);
+
+ return error;
+}
+
+/**
+ * pm_cancel_autosuspend - Cancel a pending autosuspend request for given device
+ * @dev: Device to handle.
+ *
+ * This routine is only supposed to be called when the run-time PM workqueue is
+ * frozen (i.e. during system-wide suspend or hibernation) when it is guaranteed
+ * that no work items are being executed.
+ */
+void pm_cancel_autosuspend(struct device *dev)
+{
+ spin_lock(&dev->power.lock);
+
+ cancel_delayed_work(&dev->power.suspend_work);
+ pm_runtime_reset(dev);
+
+ spin_unlock(&dev->power.lock);
+}
+
+/**
+ * pm_cancel_autoresume - Cancel a pending autoresume request for given device
+ * @dev: Device to handle.
+ *
+ * This routine is only supposed to be called when the run-time PM workqueue is
+ * frozen (i.e. during system-wide suspend or hibernation) when it is guaranteed
+ * that no work items are being executed.
+ */
+void pm_cancel_autoresume(struct device *dev)
+{
+ spin_lock(&dev->power.lock);
+
+ work_clear_pending(&dev->power.resume_work);
+ pm_runtime_reset(dev);
+
+ spin_unlock(&dev->power.lock);
+}
+
+/**
+ * pm_runtime_init - Initialize run-time PM fields in given device object.
+ * @dev: Device object to handle.
+ */
+void pm_runtime_init(struct device *dev)
+{
+ pm_runtime_reset(dev);
+ spin_lock_init(&dev->power.lock);
+ INIT_DELAYED_WORK(&dev->power.suspend_work, pm_autosuspend);
+ INIT_WORK(&dev->power.resume_work, pm_autoresume);
+}
Index: linux-2.6/include/linux/pm_runtime.h
===================================================================
--- /dev/null
+++ linux-2.6/include/linux/pm_runtime.h
@@ -0,0 +1,50 @@
+/*
+ * pm_runtime.h - Device run-time power management helper functions.
+ *
+ * Copyright (C) 2009 Rafael J. Wysocki <rjw@xxxxxxx>
+ *
+ * This file is released under the GPLv2.
+ */
+
+#ifndef _LINUX_PM_RUNTIME_H
+#define _LINUX_PM_RUNTIME_H
+
+#include <linux/device.h>
+#include <linux/pm.h>
+
+#ifdef CONFIG_PM_RUNTIME
+extern struct workqueue_struct *pm_wq;
+
+extern void pm_runtime_init(struct device *dev);
+extern void pm_request_suspend(struct device *dev, unsigned long delay);
+extern void pm_request_resume(struct device *dev);
+extern int pm_resume_sync(struct device *dev);
+extern void pm_cancel_autosuspend(struct device *dev);
+extern void pm_cancel_autoresume(struct device *dev);
+
+static inline struct device *suspend_work_to_device(struct delayed_work *work)
+{
+ struct dev_pm_info *dpi;
+
+ dpi = container_of(work, struct dev_pm_info, suspend_work);
+ return container_of(dpi, struct device, power);
+}
+
+static inline struct device *resume_work_to_device(struct work_struct *work)
+{
+ struct dev_pm_info *dpi;
+
+ dpi = container_of(work, struct dev_pm_info, resume_work);
+ return container_of(dpi, struct device, power);
+}
+
+#else /* !CONFIG_PM_RUNTIME */
+static inline void pm_runtime_init(struct device *dev) {}
+static inline void pm_request_suspend(struct device *dev, unsigned long delay);
+static inline void pm_request_resume(struct device *dev) {}
+static inline int pm_resume_sync(struct device *dev) { return -ENOSYS; }
+static inline void pm_cancel_autosuspend(struct device *dev) {}
+static inline void pm_cancel_autoresume(struct device *dev) {}
+#endif /* !CONFIG_PM_RUNTIME */
+
+#endif
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
@@ -21,6 +21,7 @@
#include <linux/kallsyms.h>
#include <linux/mutex.h>
#include <linux/pm.h>
+#include <linux/pm_runtime.h>
#include <linux/resume-trace.h>
#include <linux/rwsem.h>
#include <linux/interrupt.h>
@@ -88,6 +89,7 @@ void device_pm_add(struct device *dev)
}
list_add_tail(&dev->power.entry, &dpm_list);
+ pm_runtime_init(dev);
mutex_unlock(&dpm_list_mtx);
}
--
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