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Commit eaafbc3a authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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USB: Allow autosuspend delay to equal 0 



This patch (as867) adds an entry for the new power/autosuspend
attribute in Documentation/ABI/testing, and it changes the behavior of
the delay value.  Now a delay of 0 means to autosuspend as soon as
possible, and negative values will prevent autosuspend.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 6b157c9b

Documentation/ABI/testing/sysfs-bus-usb

0 → 100644
+15 −0
Original line number Diff line number Diff line 
What:		/sys/bus/usb/devices/.../power/autosuspend

Date:		March 2007

KernelVersion:	2.6.21

Contact:	Alan Stern <stern@rowland.harvard.edu>

Description:

		Each USB device directory will contain a file named

		power/autosuspend.  This file holds the time (in seconds)

		the device must be idle before it will be autosuspended.

		0 means the device will be autosuspended as soon as

		possible.  Negative values will prevent the device from

		being autosuspended at all, and writing a negative value

		will resume the device if it is already suspended.



		The autosuspend delay for newly-created devices is set to

		the value of the usbcore.autosuspend module parameter.

Documentation/kernel-parameters.txt

+1 −1
Original line number Diff line number Diff line
@@ -1792,7 +1792,7 @@ and is between 256 and 4096 characters. It is defined in the file 
			for newly-detected USB devices (default 2).  This

			is the time required before an idle device will be

			autosuspended.  Devices for which the delay is set

			to 0 won't be autosuspended at all.

			to a negative value won't be autosuspended at all.



	usbhid.mousepoll=

			[USBHID] The interval which mice are to be polled at.

drivers/usb/core/driver.c

+1 −1
Original line number Diff line number Diff line
@@ -970,7 +970,7 @@ static int autosuspend_check(struct usb_device *udev) 
	udev->do_remote_wakeup = device_may_wakeup(&udev->dev);

	if (udev->pm_usage_cnt > 0)

		return -EBUSY;

	if (!udev->autosuspend_delay)

	if (udev->autosuspend_delay < 0)

		return -EPERM;



	if (udev->actconfig) {

drivers/usb/core/sysfs.c

+10 −6
Original line number Diff line number Diff line
@@ -165,7 +165,7 @@ 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);

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

}



static ssize_t
@@ -173,17 +173,21 @@ 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;

	int value;



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

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

			value <= - INT_MAX/HZ)

		return -EINVAL;

	value *= HZ;



	old = udev->autosuspend_delay;

	udev->autosuspend_delay = value;

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

	if (value >= 0)

		usb_try_autosuspend_device(udev);



	else {

		usb_lock_device(udev);

		usb_external_resume_device(udev);

		usb_unlock_device(udev);

	}

	return count;

}

drivers/usb/core/usb.c

+1 −1
Original line number Diff line number Diff line
@@ -55,7 +55,7 @@ struct workqueue_struct *ksuspend_usb_wq; 
#ifdef	CONFIG_USB_SUSPEND

static int usb_autosuspend_delay = 2;		/* Default delay value,

						 * in seconds */

module_param_named(autosuspend, usb_autosuspend_delay, uint, 0644);

module_param_named(autosuspend, usb_autosuspend_delay, int, 0644);

MODULE_PARM_DESC(autosuspend, "default autosuspend delay");



#else