This patch (as1303) revises the USB Power Management infrastructure to
make it compatible with the new driver-model Runtime PM framework:
Drivers are no longer allowed to access intf->pm_usage_cnt
directly; the PM framework manages its own usage counters.
usb_autopm_set_interface() is eliminated, because it directly
sets intf->pm_usage_cnt.
usb_autopm_enable() and usb_autopm_disable() are eliminated,
because they call usb_autopm_set_interface().
usb_autopm_get_interface_no_resume() and
usb_autopm_put_interface_no_suspend() are added. They
correspond to pm_runtime_get_noresume() and
pm_runtime_put_noidle() in the PM framework.
The power/level attribute no longer accepts "suspend", only
"on" and "auto". The PM framework doesn't allow devices to be
forced into a suspended mode.
The hub driver contains the only code that violates the new
guidelines. It is updated to use the new interface routines instead.
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
---
Index: usb-2.6/Documentation/usb/power-management.txt
===================================================================
--- usb-2.6.orig/Documentation/usb/power-management.txt
+++ usb-2.6/Documentation/usb/power-management.txt
@@ -2,7 +2,7 @@
Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
- October 5, 2007
+ November 10, 2009
@@ -123,9 +123,9 @@ relevant attribute files are: wakeup, le
power/level
- This file contains one of three words: "on", "auto",
- or "suspend". You can write those words to the file
- to change the device's setting.
+ This file contains one of two words: "on" or "auto".
+ You can write those words to the file to change the
+ device's setting.
"on" means that the device should be resumed and
autosuspend is not allowed. (Of course, system
@@ -134,10 +134,10 @@ relevant attribute files are: wakeup, le
"auto" is the normal state in which the kernel is
allowed to autosuspend and autoresume the device.
- "suspend" means that the device should remain
- suspended, and autoresume is not allowed. (But remote
- wakeup may still be allowed, since it is controlled
- separately by the power/wakeup attribute.)
+ (In kernels up to 2.6.32, you could also specify
+ "suspend", meaning that the device should remain
+ suspended and autoresume was not allowed. This
+ setting is no longer supported.)
power/autosuspend
@@ -313,13 +313,14 @@ three of the methods listed above. In a
that it supports autosuspend by setting the .supports_autosuspend flag
in its usb_driver structure. It is then responsible for informing the
USB core whenever one of its interfaces becomes busy or idle. The
-driver does so by calling these five functions:
+driver does so by calling these six functions:
int usb_autopm_get_interface(struct usb_interface *intf);
void usb_autopm_put_interface(struct usb_interface *intf);
- int usb_autopm_set_interface(struct usb_interface *intf);
int usb_autopm_get_interface_async(struct usb_interface *intf);
void usb_autopm_put_interface_async(struct usb_interface *intf);
+ void usb_autopm_get_interface_no_resume(struct usb_interface *intf);
+ void usb_autopm_put_interface_no_suspend(struct usb_interface *intf);
The functions work by maintaining a counter in the usb_interface
structure. When intf->pm_usage_count is > 0 then the interface is
@@ -331,11 +332,13 @@ considered to be idle, and the kernel ma
associated with the device itself rather than any of its interfaces.
This field is used only by the USB core.)
-The driver owns intf->pm_usage_count; it can modify the value however
-and whenever it likes. A nice aspect of the non-async usb_autopm_*
-routines is that the changes they make are protected by the usb_device
-structure's PM mutex (udev->pm_mutex); however drivers may change
-pm_usage_count without holding the mutex. Drivers using the async
+Drivers must not modify intf->pm_usage_count directly; its value
+should be changed only be using the functions listed above. Drivers
+are responsible for insuring that the overall change to pm_usage_count
+during their lifetime balances out to 0 (it may be necessary for the
+disconnect method to call usb_autopm_put_interface() one or more times
+to fulfill this requirement). The first two routines use the PM mutex
+in struct usb_device for mutual exclusion; drivers using the async
routines are responsible for their own synchronization and mutual
exclusion.
@@ -347,11 +350,6 @@ exclusion.
attempts an autosuspend if the new value is <= 0 and the
device isn't suspended.
- usb_autopm_set_interface() leaves pm_usage_count alone.
- It attempts an autoresume if the value is > 0 and the device
- is suspended, and it attempts an autosuspend if the value is
- <= 0 and the device isn't suspended.
-
usb_autopm_get_interface_async() and
usb_autopm_put_interface_async() do almost the same things as
their non-async counterparts. The differences are: they do
@@ -360,13 +358,11 @@ exclusion.
such as an URB's completion handler, but when they return the
device will not generally not yet be in the desired state.
-There also are a couple of utility routines drivers can use:
-
- usb_autopm_enable() sets pm_usage_cnt to 0 and then calls
- usb_autopm_set_interface(), which will attempt an autosuspend.
-
- usb_autopm_disable() sets pm_usage_cnt to 1 and then calls
- usb_autopm_set_interface(), which will attempt an autoresume.
+ usb_autopm_get_interface_no_resume() and
+ usb_autopm_put_interface_no_suspend() merely increment or
+ decrement the pm_usage_count value; they do not attempt to
+ carry out an autoresume or an autosuspend. Hence they can be
+ called in an atomic context.
The conventional usage pattern is that a driver calls
usb_autopm_get_interface() in its open routine and
@@ -400,11 +396,11 @@ though, setting this flag won't cause th
Normally a driver would set this flag in its probe method, at which
time the device is guaranteed not to be autosuspended.)
-The usb_autopm_* routines have to run in a sleepable process context;
-they must not be called from an interrupt handler or while holding a
-spinlock. In fact, the entire autosuspend mechanism is not well geared
-toward interrupt-driven operation. However there is one thing a
-driver can do in an interrupt handler:
+The synchronous usb_autopm_* routines have to run in a sleepable
+process context; they must not be called from an interrupt handler or
+while holding a spinlock. In fact, the entire autosuspend mechanism
+is not well geared toward interrupt-driven operation. However there
+is one thing a driver can do in an interrupt handler:
usb_mark_last_busy(struct usb_device *udev);
Index: usb-2.6/include/linux/usb.h
===================================================================
--- usb-2.6.orig/include/linux/usb.h
+++ usb-2.6/include/linux/usb.h
@@ -432,7 +432,6 @@ struct usb_tt;
* @do_remote_wakeup: remote wakeup should be enabled
* @reset_resume: needs reset instead of resume
* @autosuspend_disabled: autosuspend disabled by the user
- * @autoresume_disabled: autoresume disabled by the user
* @skip_sys_resume: skip the next system resume
* @wusb_dev: if this is a Wireless USB device, link to the WUSB
* specific data for the device.
@@ -516,7 +515,6 @@ struct usb_device {
unsigned do_remote_wakeup:1;
unsigned reset_resume:1;
unsigned autosuspend_disabled:1;
- unsigned autoresume_disabled:1;
unsigned skip_sys_resume:1;
#endif
struct wusb_dev *wusb_dev;
@@ -542,22 +540,20 @@ extern struct usb_device *usb_find_devic
/* USB autosuspend and autoresume */
#ifdef CONFIG_USB_SUSPEND
-extern int usb_autopm_set_interface(struct usb_interface *intf);
extern int usb_autopm_get_interface(struct usb_interface *intf);
extern void usb_autopm_put_interface(struct usb_interface *intf);
extern int usb_autopm_get_interface_async(struct usb_interface *intf);
extern void usb_autopm_put_interface_async(struct usb_interface *intf);
-static inline void usb_autopm_enable(struct usb_interface *intf)
+static inline void usb_autopm_get_interface_no_resume(
+ struct usb_interface *intf)
{
- atomic_set(&intf->pm_usage_cnt, 0);
- usb_autopm_set_interface(intf);
+ atomic_inc(&intf->pm_usage_cnt);
}
-
-static inline void usb_autopm_disable(struct usb_interface *intf)
+static inline void usb_autopm_put_interface_no_suspend(
+ struct usb_interface *intf)
{
- atomic_set(&intf->pm_usage_cnt, 1);
- usb_autopm_set_interface(intf);
+ atomic_dec(&intf->pm_usage_cnt);
}
static inline void usb_mark_last_busy(struct usb_device *udev)
@@ -567,12 +563,8 @@ static inline void usb_mark_last_busy(st
#else
-static inline int usb_autopm_set_interface(struct usb_interface *intf)
-{ return 0; }
-
static inline int usb_autopm_get_interface(struct usb_interface *intf)
{ return 0; }
-
static inline int usb_autopm_get_interface_async(struct usb_interface *intf)
{ return 0; }
@@ -580,9 +572,11 @@ static inline void usb_autopm_put_interf
{ }
static inline void usb_autopm_put_interface_async(struct usb_interface *intf)
{ }
-static inline void usb_autopm_enable(struct usb_interface *intf)
+static inline void usb_autopm_get_interface_no_resume(
+ struct usb_interface *intf)
{ }
-static inline void usb_autopm_disable(struct usb_interface *intf)
+static inline void usb_autopm_put_interface_no_suspend(
+ struct usb_interface *intf)
{ }
static inline void usb_mark_last_busy(struct usb_device *udev)
{ }
Index: usb-2.6/drivers/usb/core/driver.c
===================================================================
--- usb-2.6.orig/drivers/usb/core/driver.c
+++ usb-2.6/drivers/usb/core/driver.c
@@ -948,8 +948,6 @@ static int usb_resume_device(struct usb_
done:
dev_vdbg(&udev->dev, "%s: status %d\n", __func__, status);
- if (status == 0)
- udev->autoresume_disabled = 0;
return status;
}
@@ -1280,11 +1278,6 @@ static int usb_resume_both(struct usb_de
/* Propagate the resume up the tree, if necessary */
if (udev->state == USB_STATE_SUSPENDED) {
- if ((msg.event & PM_EVENT_AUTO) &&
- udev->autoresume_disabled) {
- status = -EPERM;
- goto done;
- }
if (parent) {
status = usb_autoresume_device(parent);
if (status == 0) {
@@ -1638,8 +1631,6 @@ int usb_autopm_get_interface_async(struc
if (intf->condition == USB_INTERFACE_UNBOUND)
status = -ENODEV;
- else if (udev->autoresume_disabled)
- status = -EPERM;
else {
atomic_inc(&intf->pm_usage_cnt);
if (atomic_read(&intf->pm_usage_cnt) > 0 &&
@@ -1652,28 +1643,6 @@ int usb_autopm_get_interface_async(struc
}
EXPORT_SYMBOL_GPL(usb_autopm_get_interface_async);
-/**
- * usb_autopm_set_interface - set a USB interface's autosuspend state
- * @intf: the usb_interface whose state should be set
- *
- * This routine sets the autosuspend state of @intf's device according
- * to @intf's usage counter, which the caller must have set previously.
- * If the counter is <= 0, the device is autosuspended (if it isn't
- * already suspended and if nothing else prevents the autosuspend). If
- * the counter is > 0, the device is autoresumed (if it isn't already
- * awake).
- */
-int usb_autopm_set_interface(struct usb_interface *intf)
-{
- int status;
-
- status = usb_autopm_do_interface(intf, 0);
- dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",
- __func__, status, atomic_read(&intf->pm_usage_cnt));
- return status;
-}
-EXPORT_SYMBOL_GPL(usb_autopm_set_interface);
-
#else
void usb_autosuspend_work(struct work_struct *work)
Index: usb-2.6/drivers/usb/core/sysfs.c
===================================================================
--- usb-2.6.orig/drivers/usb/core/sysfs.c
+++ usb-2.6/drivers/usb/core/sysfs.c
@@ -317,7 +317,6 @@ static DEVICE_ATTR(autosuspend, S_IRUGO
static const char on_string[] = "on";
static const char auto_string[] = "auto";
-static const char suspend_string[] = "suspend";
static ssize_t
show_level(struct device *dev, struct device_attribute *attr, char *buf)
@@ -325,13 +324,8 @@ show_level(struct device *dev, struct de
struct usb_device *udev = to_usb_device(dev);
const char *p = auto_string;
- if (udev->state == USB_STATE_SUSPENDED) {
- if (udev->autoresume_disabled)
- p = suspend_string;
- } else {
- if (udev->autosuspend_disabled)
- p = on_string;
- }
+ if (udev->state != USB_STATE_SUSPENDED && udev->autosuspend_disabled)
+ p = on_string;
return sprintf(buf, "%s\n", p);
}
@@ -343,7 +337,7 @@ set_level(struct device *dev, struct dev
int len = count;
char *cp;
int rc = 0;
- int old_autosuspend_disabled, old_autoresume_disabled;
+ int old_autosuspend_disabled;
cp = memchr(buf, '\n', count);
if (cp)
@@ -351,7 +345,6 @@ set_level(struct device *dev, struct dev
usb_lock_device(udev);
old_autosuspend_disabled = udev->autosuspend_disabled;
- old_autoresume_disabled = udev->autoresume_disabled;
/* Setting the flags without calling usb_pm_lock is a subject to
* races, but who cares...
@@ -359,28 +352,18 @@ set_level(struct device *dev, struct dev
if (len == sizeof on_string - 1 &&
strncmp(buf, on_string, len) == 0) {
udev->autosuspend_disabled = 1;
- udev->autoresume_disabled = 0;
rc = usb_external_resume_device(udev, PMSG_USER_RESUME);
} else if (len == sizeof auto_string - 1 &&
strncmp(buf, auto_string, len) == 0) {
udev->autosuspend_disabled = 0;
- udev->autoresume_disabled = 0;
rc = usb_external_resume_device(udev, PMSG_USER_RESUME);
- } else if (len == sizeof suspend_string - 1 &&
- strncmp(buf, suspend_string, len) == 0) {
- udev->autosuspend_disabled = 0;
- udev->autoresume_disabled = 1;
- rc = usb_external_suspend_device(udev, PMSG_USER_SUSPEND);
-
} else
rc = -EINVAL;
- if (rc) {
+ if (rc)
udev->autosuspend_disabled = old_autosuspend_disabled;
- udev->autoresume_disabled = old_autoresume_disabled;
- }
usb_unlock_device(udev);
return (rc < 0 ? rc : count);
}
Index: usb-2.6/drivers/usb/core/hub.c
===================================================================
--- usb-2.6.orig/drivers/usb/core/hub.c
+++ usb-2.6/drivers/usb/core/hub.c
@@ -71,6 +71,7 @@ struct usb_hub {
unsigned mA_per_port; /* current for each child */
+ unsigned init_done:1;
unsigned limited_power:1;
unsigned quiescing:1;
unsigned disconnected:1;
@@ -375,12 +376,13 @@ static void kick_khubd(struct usb_hub *h
{
unsigned long flags;
- /* Suppress autosuspend until khubd runs */
- atomic_set(&to_usb_interface(hub->intfdev)->pm_usage_cnt, 1);
-
spin_lock_irqsave(&hub_event_lock, flags);
if (!hub->disconnected && list_empty(&hub->event_list)) {
list_add_tail(&hub->event_list, &hub_event_list);
+
+ /* Suppress autosuspend until khubd runs */
+ usb_autopm_get_interface_no_resume(
+ to_usb_interface(hub->intfdev));
wake_up(&khubd_wait);
}
spin_unlock_irqrestore(&hub_event_lock, flags);
@@ -665,7 +667,7 @@ int usb_remove_device(struct usb_device
}
enum hub_activation_type {
- HUB_INIT, HUB_INIT2, HUB_INIT3,
+ HUB_INIT, HUB_INIT2, HUB_INIT3, /* INITs must come first */
HUB_POST_RESET, HUB_RESUME, HUB_RESET_RESUME,
};
@@ -710,8 +712,8 @@ static void hub_activate(struct usb_hub
msecs_to_jiffies(delay));
/* Suppress autosuspend until init is done */
- atomic_set(&to_usb_interface(hub->intfdev)->
- pm_usage_cnt, 1);
+ usb_autopm_get_interface_no_resume(
+ to_usb_interface(hub->intfdev));
return; /* Continues at init2: below */
} else {
hub_power_on(hub, true);
@@ -818,6 +820,7 @@ static void hub_activate(struct usb_hub
}
init3:
hub->quiescing = 0;
+ hub->init_done = 1;
status = usb_submit_urb(hub->urb, GFP_NOIO);
if (status < 0)
@@ -827,6 +830,10 @@ static void hub_activate(struct usb_hub
/* Scan all ports that need attention */
kick_khubd(hub);
+
+ /* Allow autosuspend if it was suppressed */
+ if (type <= HUB_INIT3)
+ usb_autopm_put_interface_async(to_usb_interface(hub->intfdev));
}
/* Implement the continuations for the delays above */
@@ -854,6 +861,11 @@ static void hub_quiesce(struct usb_hub *
int i;
cancel_delayed_work_sync(&hub->init_work);
+ if (!hub->init_done) {
+ hub->init_done = 1;
+ usb_autopm_put_interface_no_suspend(
+ to_usb_interface(hub->intfdev));
+ }
/* khubd and related activity won't re-trigger */
hub->quiescing = 1;
@@ -1176,7 +1188,10 @@ static void hub_disconnect(struct usb_in
/* Take the hub off the event list and don't let it be added again */
spin_lock_irq(&hub_event_lock);
- list_del_init(&hub->event_list);
+ if (!list_empty(&hub->event_list)) {
+ list_del_init(&hub->event_list);
+ usb_autopm_put_interface_no_suspend(intf);
+ }
hub->disconnected = 1;
spin_unlock_irq(&hub_event_lock);
@@ -3230,7 +3245,7 @@ static void hub_events(void)
* disconnected while waiting for the lock to succeed. */
usb_lock_device(hdev);
if (unlikely(hub->disconnected))
- goto loop;
+ goto loop2;
/* If the hub has died, clean up after it */
if (hdev->state == USB_STATE_NOTATTACHED) {
@@ -3379,11 +3394,15 @@ static void hub_events(void)
}
}
-loop_autopm:
- /* Allow autosuspend if we're not going to run again */
- if (list_empty(&hub->event_list))
- usb_autopm_enable(intf);
-loop:
+ loop_autopm:
+ /* Balance the usb_autopm_get_interface() above */
+ usb_autopm_put_interface_no_suspend(intf);
+ loop:
+ /* Balance the usb_autopm_get_interface_no_resume() in
+ * kick_khubd() and allow autosuspend.
+ */
+ usb_autopm_put_interface(intf);
+ loop2:
usb_unlock_device(hdev);
kref_put(&hub->kref, hub_release);
--
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