diff options
| -rw-r--r-- | Documentation/usb/power-management.txt | 18 | ||||
| -rw-r--r-- | drivers/usb/core/driver.c | 42 | ||||
| -rw-r--r-- | drivers/usb/core/hub.c | 3 | ||||
| -rw-r--r-- | drivers/usb/core/quirks.c | 9 | ||||
| -rw-r--r-- | drivers/usb/core/sysfs.c | 23 | ||||
| -rw-r--r-- | include/linux/usb.h | 8 |
6 files changed, 82 insertions, 21 deletions
diff --git a/Documentation/usb/power-management.txt b/Documentation/usb/power-management.txt index 3bf6818..e3fa189 100644 --- a/Documentation/usb/power-management.txt +++ b/Documentation/usb/power-management.txt @@ -229,6 +229,11 @@ necessary operations by hand or add them to a udev script. You can also change the idle-delay time; 2 seconds is not the best choice for every device. +If a driver knows that its device has proper suspend/resume support, +it can enable autosuspend all by itself. For example, the video +driver for a laptop's webcam might do this, since these devices are +rarely used and so should normally be autosuspended. + Sometimes it turns out that even when a device does work okay with autosuspend there are still problems. For example, there are experimental patches adding autosuspend support to the usbhid driver, @@ -384,6 +389,19 @@ autosuspend, there's no delay for an autoresume. Other parts of the driver interface ----------------------------------- +Drivers can enable autosuspend for their devices by calling + + usb_enable_autosuspend(struct usb_device *udev); + +in their probe() routine, if they know that the device is capable of +suspending and resuming correctly. This is exactly equivalent to +writing "auto" to the device's power/level attribute. Likewise, +drivers can disable autosuspend by calling + + usb_disable_autosuspend(struct usb_device *udev); + +This is exactly the same as writing "on" to the power/level attribute. + Sometimes a driver needs to make sure that remote wakeup is enabled during autosuspend. For example, there's not much point autosuspending a keyboard if the user can't cause the keyboard to do a diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c index 2b39583..057eeab 100644 --- a/drivers/usb/core/driver.c +++ b/drivers/usb/core/driver.c @@ -1415,6 +1415,48 @@ static int usb_resume_both(struct usb_device *udev, pm_message_t msg) #ifdef CONFIG_USB_SUSPEND +/** + * usb_enable_autosuspend - allow a USB device to be autosuspended + * @udev: the USB device which may be autosuspended + * + * This routine allows @udev to be autosuspended. An autosuspend won't + * take place until the autosuspend_delay has elapsed and all the other + * necessary conditions are satisfied. + * + * The caller must hold @udev's device lock. + */ +int usb_enable_autosuspend(struct usb_device *udev) +{ + if (udev->autosuspend_disabled) { + udev->autosuspend_disabled = 0; + usb_autosuspend_device(udev); + } + return 0; +} +EXPORT_SYMBOL_GPL(usb_enable_autosuspend); + +/** + * usb_disable_autosuspend - prevent a USB device from being autosuspended + * @udev: the USB device which may not be autosuspended + * + * This routine prevents @udev from being autosuspended and wakes it up + * if it is already autosuspended. + * + * The caller must hold @udev's device lock. + */ +int usb_disable_autosuspend(struct usb_device *udev) +{ + int rc = 0; + + if (!udev->autosuspend_disabled) { + rc = usb_autoresume_device(udev); + if (rc == 0) + udev->autosuspend_disabled = 1; + } + return rc; +} +EXPORT_SYMBOL_GPL(usb_disable_autosuspend); + /* Internal routine to adjust a device's usage counter and change * its autosuspend state. */ diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index bfa6123..746f26f 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -1224,6 +1224,9 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id) desc = intf->cur_altsetting; hdev = interface_to_usbdev(intf); + /* Hubs have proper suspend/resume support */ + usb_enable_autosuspend(hdev); + if (hdev->level == MAX_TOPO_LEVEL) { dev_err(&intf->dev, "Unsupported bus topology: hub nested too deep\n"); diff --git a/drivers/usb/core/quirks.c b/drivers/usb/core/quirks.c index 0b68922..4314f25 100644 --- a/drivers/usb/core/quirks.c +++ b/drivers/usb/core/quirks.c @@ -103,11 +103,10 @@ void usb_detect_quirks(struct usb_device *udev) dev_dbg(&udev->dev, "USB quirks for this device: %x\n", udev->quirks); - /* By default, disable autosuspend for all non-hubs */ -#ifdef CONFIG_USB_SUSPEND - if (udev->descriptor.bDeviceClass != USB_CLASS_HUB) - udev->autosuspend_disabled = 1; -#endif + /* By default, disable autosuspend for all devices. The hub driver + * will enable it for hubs. + */ + usb_disable_autosuspend(udev); /* For the present, all devices default to USB-PERSIST enabled */ #if 0 /* was: #ifdef CONFIG_PM */ diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c index 5a1a0e2..313e241 100644 --- a/drivers/usb/core/sysfs.c +++ b/drivers/usb/core/sysfs.c @@ -389,34 +389,25 @@ set_level(struct device *dev, struct device_attribute *attr, struct usb_device *udev = to_usb_device(dev); int len = count; char *cp; - int rc = 0; - int old_autosuspend_disabled; + int rc; cp = memchr(buf, '\n', count); if (cp) len = cp - buf; usb_lock_device(udev); - old_autosuspend_disabled = udev->autosuspend_disabled; - /* Setting the flags without calling usb_pm_lock is a subject to - * races, but who cares... - */ if (len == sizeof on_string - 1 && - strncmp(buf, on_string, len) == 0) { - udev->autosuspend_disabled = 1; - rc = usb_external_resume_device(udev, PMSG_USER_RESUME); + strncmp(buf, on_string, len) == 0) + rc = usb_disable_autosuspend(udev); - } else if (len == sizeof auto_string - 1 && - strncmp(buf, auto_string, len) == 0) { - udev->autosuspend_disabled = 0; - rc = usb_external_resume_device(udev, PMSG_USER_RESUME); + else if (len == sizeof auto_string - 1 && + strncmp(buf, auto_string, len) == 0) + rc = usb_enable_autosuspend(udev); - } else + else rc = -EINVAL; - if (rc) - udev->autosuspend_disabled = old_autosuspend_disabled; usb_unlock_device(udev); return (rc < 0 ? rc : count); } diff --git a/include/linux/usb.h b/include/linux/usb.h index 332eaea..e6419ac 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -542,6 +542,9 @@ extern struct usb_device *usb_find_device(u16 vendor_id, u16 product_id); /* USB autosuspend and autoresume */ #ifdef CONFIG_USB_SUSPEND +extern int usb_enable_autosuspend(struct usb_device *udev); +extern int usb_disable_autosuspend(struct usb_device *udev); + 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); @@ -565,6 +568,11 @@ static inline void usb_mark_last_busy(struct usb_device *udev) #else +static inline int usb_enable_autosuspend(struct usb_device *udev) +{ return 0; } +static inline int usb_disable_autosuspend(struct usb_device *udev) +{ return 0; } + 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) |