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-rw-r--r--Documentation/usb/power-management.txt22
-rw-r--r--drivers/usb/core/driver.c86
-rw-r--r--drivers/usb/core/hub.c5
-rw-r--r--drivers/usb/core/usb.c1
-rw-r--r--drivers/usb/core/usb.h1
-rw-r--r--include/linux/usb.h9
6 files changed, 117 insertions, 7 deletions
diff --git a/Documentation/usb/power-management.txt b/Documentation/usb/power-management.txt
index e48ea1d5101..ad642615ad4 100644
--- a/Documentation/usb/power-management.txt
+++ b/Documentation/usb/power-management.txt
@@ -313,11 +313,13 @@ three of the methods listed above. In addition, a driver indicates
that it supports autosuspend by setting the .supports_autosuspend flag
in its usb_driver structure. It is then responsible for informing the
USB core whenever one of its interfaces becomes busy or idle. The
-driver does so by calling these three functions:
+driver does so by calling these five functions:
int usb_autopm_get_interface(struct usb_interface *intf);
void usb_autopm_put_interface(struct usb_interface *intf);
int usb_autopm_set_interface(struct usb_interface *intf);
+ int usb_autopm_get_interface_async(struct usb_interface *intf);
+ void usb_autopm_put_interface_async(struct usb_interface *intf);
The functions work by maintaining a counter in the usb_interface
structure. When intf->pm_usage_count is > 0 then the interface is
@@ -330,10 +332,12 @@ associated with the device itself rather than any of its interfaces.
This field is used only by the USB core.)
The driver owns intf->pm_usage_count; it can modify the value however
-and whenever it likes. A nice aspect of the usb_autopm_* routines is
-that the changes they make are protected by the usb_device structure's
-PM mutex (udev->pm_mutex); however drivers may change pm_usage_count
-without holding the mutex.
+and whenever it likes. A nice aspect of the non-async usb_autopm_*
+routines is that the changes they make are protected by the usb_device
+structure's PM mutex (udev->pm_mutex); however drivers may change
+pm_usage_count without holding the mutex. Drivers using the async
+routines are responsible for their own synchronization and mutual
+exclusion.
usb_autopm_get_interface() increments pm_usage_count and
attempts an autoresume if the new value is > 0 and the
@@ -348,6 +352,14 @@ without holding the mutex.
is suspended, and it attempts an autosuspend if the value is
<= 0 and the device isn't suspended.
+ usb_autopm_get_interface_async() and
+ usb_autopm_put_interface_async() do almost the same things as
+ their non-async counterparts. The differences are: they do
+ not acquire the PM mutex, and they use a workqueue to do their
+ jobs. As a result they can be called in an atomic context,
+ such as an URB's completion handler, but when they return the
+ device will not generally not yet be in the desired state.
+
There also are a couple of utility routines drivers can use:
usb_autopm_enable() sets pm_usage_cnt to 0 and then calls
diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 8c081308b0e..23b3c7e79d4 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -1341,6 +1341,19 @@ void usb_autosuspend_work(struct work_struct *work)
usb_autopm_do_device(udev, 0);
}
+/* usb_autoresume_work - callback routine to autoresume a USB device */
+void usb_autoresume_work(struct work_struct *work)
+{
+ struct usb_device *udev =
+ container_of(work, struct usb_device, autoresume);
+
+ /* Wake it up, let the drivers do their thing, and then put it
+ * back to sleep.
+ */
+ if (usb_autopm_do_device(udev, 1) == 0)
+ usb_autopm_do_device(udev, -1);
+}
+
/**
* usb_autosuspend_device - delayed autosuspend of a USB device and its interfaces
* @udev: the usb_device to autosuspend
@@ -1492,6 +1505,45 @@ void usb_autopm_put_interface(struct usb_interface *intf)
EXPORT_SYMBOL_GPL(usb_autopm_put_interface);
/**
+ * usb_autopm_put_interface_async - decrement a USB interface's PM-usage counter
+ * @intf: the usb_interface whose counter should be decremented
+ *
+ * This routine does essentially the same thing as
+ * usb_autopm_put_interface(): it decrements @intf's usage counter and
+ * queues a delayed autosuspend request if the counter is <= 0. The
+ * difference is that it does not acquire the device's pm_mutex;
+ * callers must handle all synchronization issues themselves.
+ *
+ * Typically a driver would call this routine during an URB's completion
+ * handler, if no more URBs were pending.
+ *
+ * This routine can run in atomic context.
+ */
+void usb_autopm_put_interface_async(struct usb_interface *intf)
+{
+ struct usb_device *udev = interface_to_usbdev(intf);
+ int status = 0;
+
+ if (intf->condition == USB_INTERFACE_UNBOUND) {
+ status = -ENODEV;
+ } else {
+ udev->last_busy = jiffies;
+ --intf->pm_usage_cnt;
+ if (udev->autosuspend_disabled || udev->autosuspend_delay < 0)
+ status = -EPERM;
+ else if (intf->pm_usage_cnt <= 0 &&
+ !timer_pending(&udev->autosuspend.timer)) {
+ queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,
+ round_jiffies_relative(
+ udev->autosuspend_delay));
+ }
+ }
+ dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",
+ __func__, status, intf->pm_usage_cnt);
+}
+EXPORT_SYMBOL_GPL(usb_autopm_put_interface_async);
+
+/**
* usb_autopm_get_interface - increment a USB interface's PM-usage counter
* @intf: the usb_interface whose counter should be incremented
*
@@ -1537,6 +1589,37 @@ int usb_autopm_get_interface(struct usb_interface *intf)
EXPORT_SYMBOL_GPL(usb_autopm_get_interface);
/**
+ * usb_autopm_get_interface_async - increment a USB interface's PM-usage counter
+ * @intf: the usb_interface whose counter should be incremented
+ *
+ * This routine does much the same thing as
+ * usb_autopm_get_interface(): it increments @intf's usage counter and
+ * queues an autoresume request if the result is > 0. The differences
+ * are that it does not acquire the device's pm_mutex (callers must
+ * handle all synchronization issues themselves), and it does not
+ * autoresume the device directly (it only queues a request). After a
+ * successful call, the device will generally not yet be resumed.
+ *
+ * This routine can run in atomic context.
+ */
+int usb_autopm_get_interface_async(struct usb_interface *intf)
+{
+ struct usb_device *udev = interface_to_usbdev(intf);
+ int status = 0;
+
+ if (intf->condition == USB_INTERFACE_UNBOUND)
+ status = -ENODEV;
+ else if (udev->autoresume_disabled)
+ status = -EPERM;
+ else if (++intf->pm_usage_cnt > 0 && udev->state == USB_STATE_SUSPENDED)
+ queue_work(ksuspend_usb_wq, &udev->autoresume);
+ dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",
+ __func__, status, intf->pm_usage_cnt);
+ return status;
+}
+EXPORT_SYMBOL_GPL(usb_autopm_get_interface_async);
+
+/**
* usb_autopm_set_interface - set a USB interface's autosuspend state
* @intf: the usb_interface whose state should be set
*
@@ -1563,6 +1646,9 @@ EXPORT_SYMBOL_GPL(usb_autopm_set_interface);
void usb_autosuspend_work(struct work_struct *work)
{}
+void usb_autoresume_work(struct work_struct *work)
+{}
+
#endif /* CONFIG_USB_SUSPEND */
/**
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index b19cbfcd51d..95fb3104ba4 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1374,8 +1374,9 @@ static void usb_stop_pm(struct usb_device *udev)
usb_autosuspend_device(udev->parent);
usb_pm_unlock(udev);
- /* Stop any autosuspend requests already submitted */
- cancel_rearming_delayed_work(&udev->autosuspend);
+ /* Stop any autosuspend or autoresume requests already submitted */
+ cancel_delayed_work_sync(&udev->autosuspend);
+ cancel_work_sync(&udev->autoresume);
}
#else
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index 400fa4cc9a3..44f2fc750b6 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -402,6 +402,7 @@ struct usb_device *usb_alloc_dev(struct usb_device *parent,
#ifdef CONFIG_PM
mutex_init(&dev->pm_mutex);
INIT_DELAYED_WORK(&dev->autosuspend, usb_autosuspend_work);
+ INIT_WORK(&dev->autoresume, usb_autoresume_work);
dev->autosuspend_delay = usb_autosuspend_delay * HZ;
dev->connect_time = jiffies;
dev->active_duration = -jiffies;
diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h
index 9a1a45ac3ad..b60ebb4de1a 100644
--- a/drivers/usb/core/usb.h
+++ b/drivers/usb/core/usb.h
@@ -45,6 +45,7 @@ extern int usb_suspend(struct device *dev, pm_message_t msg);
extern int usb_resume(struct device *dev);
extern void usb_autosuspend_work(struct work_struct *work);
+extern void usb_autoresume_work(struct work_struct *work);
extern int usb_port_suspend(struct usb_device *dev);
extern int usb_port_resume(struct usb_device *dev);
extern int usb_external_suspend_device(struct usb_device *udev,
diff --git a/include/linux/usb.h b/include/linux/usb.h
index f72aa51f7bc..859a88e6ce9 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -398,6 +398,7 @@ struct usb_tt;
* @urbnum: number of URBs submitted for the whole device
* @active_duration: total time device is not suspended
* @autosuspend: for delayed autosuspends
+ * @autoresume: for autoresumes requested while in_interrupt
* @pm_mutex: protects PM operations
* @last_busy: time of last use
* @autosuspend_delay: in jiffies
@@ -476,6 +477,7 @@ struct usb_device {
#ifdef CONFIG_PM
struct delayed_work autosuspend;
+ struct work_struct autoresume;
struct mutex pm_mutex;
unsigned long last_busy;
@@ -513,6 +515,8 @@ extern struct usb_device *usb_find_device(u16 vendor_id, u16 product_id);
extern int usb_autopm_set_interface(struct usb_interface *intf);
extern int usb_autopm_get_interface(struct usb_interface *intf);
extern void usb_autopm_put_interface(struct usb_interface *intf);
+extern int usb_autopm_get_interface_async(struct usb_interface *intf);
+extern void usb_autopm_put_interface_async(struct usb_interface *intf);
static inline void usb_autopm_enable(struct usb_interface *intf)
{
@@ -539,8 +543,13 @@ static inline int usb_autopm_set_interface(struct usb_interface *intf)
static inline int usb_autopm_get_interface(struct usb_interface *intf)
{ return 0; }
+static inline int usb_autopm_get_interface_async(struct usb_interface *intf)
+{ return 0; }
+
static inline void usb_autopm_put_interface(struct usb_interface *intf)
{ }
+static inline void usb_autopm_put_interface_async(struct usb_interface *intf)
+{ }
static inline void usb_autopm_enable(struct usb_interface *intf)
{ }
static inline void usb_autopm_disable(struct usb_interface *intf)