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Commit 19c26239 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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USB: export autosuspend delay in sysfs 



This patch (as861) adds sysfs attributes to expose the autosuspend
delay value for each USB device.  If the user changes the delay from 0
(no autosuspend) to a positive value, an autosuspend is attempted.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent dfa87c82

drivers/usb/core/driver.c

+20 −0
Original line number Diff line number Diff line
@@ -1224,6 +1224,26 @@ void usb_autosuspend_device(struct usb_device *udev) 
	//		__FUNCTION__, udev->pm_usage_cnt);

}



/**

 * usb_try_autosuspend_device - attempt an autosuspend of a USB device and its interfaces

 * @udev: the usb_device to autosuspend

 *

 * This routine should be called when a core subsystem thinks @udev may

 * be ready to autosuspend.

 *

 * @udev's usage counter left unchanged.  If it or any of the usage counters

 * for an active interface is greater than 0, or autosuspend is not allowed

 * for any other reason, no autosuspend request will be queued.

 *

 * This routine can run only in process context.

 */

void usb_try_autosuspend_device(struct usb_device *udev)

{

	usb_autopm_do_device(udev, 0);

	// dev_dbg(&udev->dev, "%s: cnt %d\n",

	// 		__FUNCTION__, udev->pm_usage_cnt);

}



/**

 * usb_autoresume_device - immediately autoresume a USB device and its interfaces

 * @udev: the usb_device to autoresume

drivers/usb/core/sysfs.c

+64 −0
Original line number Diff line number Diff line
@@ -158,6 +158,65 @@ show_quirks(struct device *dev, struct device_attribute *attr, char *buf) 
}

static DEVICE_ATTR(quirks, S_IRUGO, show_quirks, NULL);



#ifdef	CONFIG_USB_SUSPEND



static ssize_t

show_autosuspend(struct device *dev, struct device_attribute *attr, char *buf)

{

	struct usb_device *udev = to_usb_device(dev);



	return sprintf(buf, "%u\n", udev->autosuspend_delay / HZ);

}



static ssize_t

set_autosuspend(struct device *dev, struct device_attribute *attr,

		const char *buf, size_t count)

{

	struct usb_device *udev = to_usb_device(dev);

	unsigned value, old;



	if (sscanf(buf, "%u", &value) != 1 || value >= INT_MAX/HZ)

		return -EINVAL;

	value *= HZ;



	old = udev->autosuspend_delay;

	udev->autosuspend_delay = value;

	if (value > 0 && old == 0)

		usb_try_autosuspend_device(udev);



	return count;

}



static DEVICE_ATTR(autosuspend, S_IRUGO | S_IWUSR,

		show_autosuspend, set_autosuspend);



static char power_group[] = "power";



static int add_power_attributes(struct device *dev)

{

	int rc = 0;



	if (is_usb_device(dev))

		rc = sysfs_add_file_to_group(&dev->kobj,

				&dev_attr_autosuspend.attr,

				power_group);

	return rc;

}



static void remove_power_attributes(struct device *dev)

{

	sysfs_remove_file_from_group(&dev->kobj,

			&dev_attr_autosuspend.attr,

			power_group);

}



#else



#define add_power_attributes(dev)	0

#define remove_power_attributes(dev)	do {} while (0)



#endif	/* CONFIG_USB_SUSPEND */



/* Descriptor fields */

#define usb_descriptor_attr_le16(field, format_string)			\

static ssize_t								\
@@ -230,6 +289,10 @@ int usb_create_sysfs_dev_files(struct usb_device *udev) 
	if (retval)

		return retval;



	retval = add_power_attributes(dev);

	if (retval)

		goto error;



	if (udev->manufacturer) {

		retval = device_create_file(dev, &dev_attr_manufacturer);

		if (retval)
@@ -262,6 +325,7 @@ void usb_remove_sysfs_dev_files(struct usb_device *udev) 
	device_remove_file(dev, &dev_attr_manufacturer);

	device_remove_file(dev, &dev_attr_product);

	device_remove_file(dev, &dev_attr_serial);

	remove_power_attributes(dev);

	sysfs_remove_group(&dev->kobj, &dev_attr_grp);

}

drivers/usb/core/usb.h

+3 −1
Original line number Diff line number Diff line
@@ -66,11 +66,13 @@ static inline void usb_pm_unlock(struct usb_device *udev) {} 
#ifdef CONFIG_USB_SUSPEND



extern void usb_autosuspend_device(struct usb_device *udev);

extern void usb_try_autosuspend_device(struct usb_device *udev);

extern int usb_autoresume_device(struct usb_device *udev);



#else



#define usb_autosuspend_device(udev)		do {} while (0)

#define usb_try_autosuspend_device(udev)	do {} while (0)

static inline int usb_autoresume_device(struct usb_device *udev)

{

	return 0;