diff options
| -rw-r--r-- | Documentation/usb/power-management.txt | 22 | ||||
| -rw-r--r-- | drivers/usb/core/driver.c | 86 | ||||
| -rw-r--r-- | drivers/usb/core/hub.c | 5 | ||||
| -rw-r--r-- | drivers/usb/core/usb.c | 1 | ||||
| -rw-r--r-- | drivers/usb/core/usb.h | 1 | ||||
| -rw-r--r-- | include/linux/usb.h | 9 |
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) |