From 088f7fec8a0e683db72fd8826c5d3ab914e197b1 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Fri, 8 Jan 2010 12:56:54 -0500 Subject: USB: implement usb_enable_autosuspend This patch (as1326) adds usb_enable_autosuspend() and usb_disable_autosuspend() routines for use by drivers. If a driver knows that its device can handle suspends and resumes correctly, it can enable autosuspend all by itself. This is equivalent to the user writing "auto" to the device's power/level attribute. The implementation differs slightly from what it used to be. Now autosuspend is disabled simply by doing usb_autoresume_device() (to increment the usage counter) and enabled by doing usb_autosuspend_device() (to decrement the usage counter). The set_level() attribute method is updated to use the new routines, and the USB Power-Management documentation is updated. The patch adds a usb_enable_autosuspend() call to the hub driver's probe routine, allowing the special-case code for hubs in quirks.c to be removed. Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/driver.c | 42 ++++++++++++++++++++++++++++++++++++++++++ drivers/usb/core/hub.c | 3 +++ drivers/usb/core/quirks.c | 9 ++++----- drivers/usb/core/sysfs.c | 23 +++++++---------------- 4 files changed, 56 insertions(+), 21 deletions(-) (limited to 'drivers/usb') diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c index 2b39583040d..057eeab0600 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 bfa6123bbdb..746f26f222a 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 0b689224394..4314f259524 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 5a1a0e2b647..313e241f5cc 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); } -- cgit v1.2.3-18-g5258