USB: add "last_busy" field for use in autosuspend
This patch (as877) adds a "last_busy" field to struct usb_device, for
use by the autosuspend framework. Now if an autosuspend call comes at
a time when the device isn't busy but hasn't yet been idle for long
enough, the timer can be set to exactly the desired value. And we
will be ready to handle things like HID drivers, which can't maintain
a useful usage count and must rely on the time-of-last-use to decide
when to autosuspend.
The patch also makes some related minor improvements:
Move the calls to the autosuspend condition-checking routine
into usb_suspend_both(), which is the only place where it
really matters.
If the autosuspend timer is already running, don't stop
and restart it.
Replace immediate returns with gotos so that the optional
debugging ouput won't be bypassed.
If autoresume is disabled but the device is already awake,
don't return an error for an autoresume call.
Don't try to autoresume a device if it isn't suspended.
(Yes, this undercuts the previous change -- so sue me.)
Don't duplicate existing code in the autosuspend work routine.
Fix the kerneldoc in usb_autopm_put_interface(): If an
autoresume call fails, the usage counter is left unchanged.
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 593386e..631f305 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -932,6 +932,7 @@
{
int i;
struct usb_interface *intf;
+ long suspend_time;
/* For autosuspend, fail fast if anything is in use or autosuspend
* is disabled. Also fail if any interfaces require remote wakeup
@@ -943,6 +944,7 @@
if (udev->autosuspend_delay < 0 || udev->autosuspend_disabled)
return -EPERM;
+ suspend_time = udev->last_busy + udev->autosuspend_delay;
if (udev->actconfig) {
for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
intf = udev->actconfig->interface[i];
@@ -958,6 +960,17 @@
}
}
}
+
+ /* If everything is okay but the device hasn't been idle for long
+ * enough, queue a delayed autosuspend request.
+ */
+ suspend_time -= jiffies;
+ if (suspend_time > 0) {
+ if (!timer_pending(&udev->autosuspend.timer))
+ queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,
+ suspend_time);
+ return -EAGAIN;
+ }
return 0;
}
@@ -1010,19 +1023,18 @@
struct usb_interface *intf;
struct usb_device *parent = udev->parent;
- cancel_delayed_work(&udev->autosuspend);
- if (udev->state == USB_STATE_NOTATTACHED)
- return 0;
- if (udev->state == USB_STATE_SUSPENDED)
- return 0;
+ if (udev->state == USB_STATE_NOTATTACHED ||
+ udev->state == USB_STATE_SUSPENDED)
+ goto done;
udev->do_remote_wakeup = device_may_wakeup(&udev->dev);
if (udev->auto_pm) {
status = autosuspend_check(udev);
if (status < 0)
- return status;
+ goto done;
}
+ cancel_delayed_work(&udev->autosuspend);
/* Suspend all the interfaces and then udev itself */
if (udev->actconfig) {
@@ -1047,6 +1059,7 @@
} else if (parent)
usb_autosuspend_device(parent);
+ done:
// dev_dbg(&udev->dev, "%s: status %d\n", __FUNCTION__, status);
return status;
}
@@ -1086,14 +1099,18 @@
struct usb_interface *intf;
struct usb_device *parent = udev->parent;
- if (udev->auto_pm && udev->autoresume_disabled)
- return -EPERM;
cancel_delayed_work(&udev->autosuspend);
- if (udev->state == USB_STATE_NOTATTACHED)
- return -ENODEV;
+ if (udev->state == USB_STATE_NOTATTACHED) {
+ status = -ENODEV;
+ goto done;
+ }
/* Propagate the resume up the tree, if necessary */
if (udev->state == USB_STATE_SUSPENDED) {
+ if (udev->auto_pm && udev->autoresume_disabled) {
+ status = -EPERM;
+ goto done;
+ }
if (parent) {
status = usb_autoresume_device(parent);
if (status == 0) {
@@ -1139,24 +1156,13 @@
}
}
+ done:
// dev_dbg(&udev->dev, "%s: status %d\n", __FUNCTION__, status);
return status;
}
#ifdef CONFIG_USB_SUSPEND
-/* usb_autosuspend_work - callback routine to autosuspend a USB device */
-void usb_autosuspend_work(struct work_struct *work)
-{
- struct usb_device *udev =
- container_of(work, struct usb_device, autosuspend.work);
-
- usb_pm_lock(udev);
- udev->auto_pm = 1;
- usb_suspend_both(udev, PMSG_SUSPEND);
- usb_pm_unlock(udev);
-}
-
/* Internal routine to adjust a device's usage counter and change
* its autosuspend state.
*/
@@ -1165,20 +1171,34 @@
int status = 0;
usb_pm_lock(udev);
+ udev->auto_pm = 1;
udev->pm_usage_cnt += inc_usage_cnt;
WARN_ON(udev->pm_usage_cnt < 0);
if (inc_usage_cnt >= 0 && udev->pm_usage_cnt > 0) {
- udev->auto_pm = 1;
- status = usb_resume_both(udev);
+ if (udev->state == USB_STATE_SUSPENDED)
+ status = usb_resume_both(udev);
if (status != 0)
udev->pm_usage_cnt -= inc_usage_cnt;
- } else if (inc_usage_cnt <= 0 && autosuspend_check(udev) == 0)
- queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,
- udev->autosuspend_delay);
+ else if (inc_usage_cnt)
+ udev->last_busy = jiffies;
+ } else if (inc_usage_cnt <= 0 && udev->pm_usage_cnt <= 0) {
+ if (inc_usage_cnt)
+ udev->last_busy = jiffies;
+ status = usb_suspend_both(udev, PMSG_SUSPEND);
+ }
usb_pm_unlock(udev);
return status;
}
+/* usb_autosuspend_work - callback routine to autosuspend a USB device */
+void usb_autosuspend_work(struct work_struct *work)
+{
+ struct usb_device *udev =
+ container_of(work, struct usb_device, autosuspend.work);
+
+ usb_autopm_do_device(udev, 0);
+}
+
/**
* usb_autosuspend_device - delayed autosuspend of a USB device and its interfaces
* @udev: the usb_device to autosuspend
@@ -1270,15 +1290,20 @@
if (intf->condition == USB_INTERFACE_UNBOUND)
status = -ENODEV;
else {
+ udev->auto_pm = 1;
intf->pm_usage_cnt += inc_usage_cnt;
if (inc_usage_cnt >= 0 && intf->pm_usage_cnt > 0) {
- udev->auto_pm = 1;
- status = usb_resume_both(udev);
+ if (udev->state == USB_STATE_SUSPENDED)
+ status = usb_resume_both(udev);
if (status != 0)
intf->pm_usage_cnt -= inc_usage_cnt;
- } else if (inc_usage_cnt <= 0 && autosuspend_check(udev) == 0)
- queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,
- udev->autosuspend_delay);
+ else if (inc_usage_cnt)
+ udev->last_busy = jiffies;
+ } else if (inc_usage_cnt <= 0 && intf->pm_usage_cnt <= 0) {
+ if (inc_usage_cnt)
+ udev->last_busy = jiffies;
+ status = usb_suspend_both(udev, PMSG_SUSPEND);
+ }
}
usb_pm_unlock(udev);
return status;
@@ -1337,11 +1362,14 @@
* or @intf is unbound. A typical example would be a character-device
* driver when its device file is opened.
*
- * The routine increments @intf's usage counter. So long as the counter
- * is greater than 0, autosuspend will not be allowed for @intf or its
- * usb_device. When the driver is finished using @intf it should call
- * usb_autopm_put_interface() to decrement the usage counter and queue
- * a delayed autosuspend request (if the counter is <= 0).
+ *
+ * The routine increments @intf's usage counter. (However if the
+ * autoresume fails then the counter is re-decremented.) So long as the
+ * counter is greater than 0, autosuspend will not be allowed for @intf
+ * or its usb_device. When the driver is finished using @intf it should
+ * call usb_autopm_put_interface() to decrement the usage counter and
+ * queue a delayed autosuspend request (if the counter is <= 0).
+ *
*
* Note that @intf->pm_usage_cnt is owned by the interface driver. The
* core will not change its value other than the increment and decrement