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/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