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USB: Allow autosuspend delay to equal 0

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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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Stern 2007-03-13 16:39:15 -04:00 committed by Greg Kroah-Hartman
parent 6b157c9bf3
commit eaafbc3a8a
6 changed files with 29 additions and 10 deletions
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15
Documentation/ABI/testing/sysfs-bus-usb Normal file
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@ -0,0 +1,15 @@
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.

2
Documentation/kernel-parameters.txt
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@ -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.

2
drivers/usb/core/driver.c
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@ -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) {

16
drivers/usb/core/sysfs.c
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@ -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;
}

2
drivers/usb/core/usb.c
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@ -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

2
include/linux/usb.h
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@ -394,7 +394,7 @@ struct usb_device {
struct delayed_work autosuspend; /* for delayed autosuspends */
struct mutex pm_mutex; /* protects PM operations */
unsigned autosuspend_delay; /* in jiffies */
int autosuspend_delay; /* in jiffies */
unsigned auto_pm:1; /* autosuspend/resume in progress */
unsigned do_remote_wakeup:1; /* remote wakeup should be enabled */