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Commit 49e7cc84 authored by Sarah Sharp's avatar Sarah Sharp Committed by Greg Kroah-Hartman
Browse files

USB: Export if an interface driver supports autosuspend. 



Create a new sysfs file per interface named supports_autosuspend.  This
file returns true if an interface driver's .supports_autosuspend flag is
set.  It also returns true if the interface is unclaimed (since the USB
core will autosuspend a device if an interface is not claimed).

This new sysfs file will be useful for user space scripts to test whether
a USB device correctly auto-suspends.

Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Oliver Neukum <oliver@neukum.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent eafe5b99

Documentation/ABI/testing/sysfs-bus-usb

+16 −0
Original line number Original line Diff line number Diff line
@@ -85,3 +85,19 @@ Description: 
Users:

Users:

		PowerTOP <power@bughost.org>

		PowerTOP <power@bughost.org>

		http://www.lesswatts.org/projects/powertop/

		http://www.lesswatts.org/projects/powertop/



What:		/sys/bus/usb/device/<busnum>-<devnum>...:<config num>-<interface num>/supports_autosuspend

Date:		January 2008

KernelVersion:	2.6.27

Contact:	Sarah Sharp <sarah.a.sharp@intel.com>

Description:

		When read, this file returns 1 if the interface driver

		for this interface supports autosuspend.  It also

		returns 1 if no driver has claimed this interface, as an

		unclaimed interface will not stop the device from being

		autosuspended if all other interface drivers are idle.

		The file returns 0 if autosuspend support has not been

		added to the driver.

Users:

		USB PM tool

		git://git.moblin.org/users/sarah/usb-pm-tool/

drivers/usb/core/sysfs.c

+24 −0
Original line number Original line Diff line number Diff line
@@ -743,6 +743,29 @@ static ssize_t show_modalias(struct device *dev, 
}

}

static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);

static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);





static ssize_t show_supports_autosuspend(struct device *dev,

		struct device_attribute *attr, char *buf)

{

	struct usb_interface *intf;

	struct usb_device *udev;

	int ret;



	intf = to_usb_interface(dev);

	udev = interface_to_usbdev(intf);



	usb_lock_device(udev);

	/* Devices will be autosuspended even when an interface isn't claimed */

	if (!intf->dev.driver ||

			to_usb_driver(intf->dev.driver)->supports_autosuspend)

		ret = sprintf(buf, "%u\n", 1);

	else

		ret = sprintf(buf, "%u\n", 0);

	usb_unlock_device(udev);



	return ret;

}

static DEVICE_ATTR(supports_autosuspend, S_IRUGO, show_supports_autosuspend, NULL);



static struct attribute *intf_attrs[] = {

static struct attribute *intf_attrs[] = {

	&dev_attr_bInterfaceNumber.attr,

	&dev_attr_bInterfaceNumber.attr,

	&dev_attr_bAlternateSetting.attr,

	&dev_attr_bAlternateSetting.attr,
@@ -751,6 +774,7 @@ static struct attribute *intf_attrs[] = { 
	&dev_attr_bInterfaceSubClass.attr,

	&dev_attr_bInterfaceSubClass.attr,

	&dev_attr_bInterfaceProtocol.attr,

	&dev_attr_bInterfaceProtocol.attr,

	&dev_attr_modalias.attr,

	&dev_attr_modalias.attr,

	&dev_attr_supports_autosuspend.attr,

	NULL,

	NULL,

};

};

static struct attribute_group intf_attr_grp = {

static struct attribute_group intf_attr_grp = {