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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
new file mode 100644
index 0000000..00a8432
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -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.
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 12533a9..2017942 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1792,7 +1792,7 @@
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.
diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index abea48d..884179f 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -970,7 +970,7 @@
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) {
diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index 311d5df..731001f 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -165,7 +165,7 @@
{
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 @@
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;
}
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index 138252e..6f35dce 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -55,7 +55,7 @@
#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
diff --git a/include/linux/usb.h b/include/linux/usb.h
index 87dc75a..cc24d08 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -394,7 +394,7 @@
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 */