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usbcore: resume device resume recursion
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This patch (as717b) removes the existing recursion in hub resume code:
Resuming a hub will no longer automatically resume the devices attached
to the hub.

At the same time, it adds one level of recursion: Suspending a USB
device will automatically suspend all the device's interfaces.  Failure
at an intermediate stage will cause all the already-suspended interfaces
to be resumed. Attempts to suspend or resume an interface by itself will
do nothing, although they won't return an error.  Thus the regular
system-suspend and system-resume procedures should continue to work as
before; only runtime PM will be affected.

The patch also removes the code that tests state of the interfaces
before suspending a device.  It's no longer needed, since everything
gets suspended together.


Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Alan Stern authored and Greg Kroah-Hartman committed Sep 27, 2006
1 parent 1cc8a25 commit a8e7c56
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Showing 4 changed files with 70 additions and 105 deletions.
63 changes: 55 additions & 8 deletions drivers/usb/core/driver.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -783,7 +783,7 @@ static int resume_device(struct usb_device *udev)
return udriver->resume(udev);
}

/* Caller has locked intf */
/* Caller has locked intf's usb_device */
static int suspend_interface(struct usb_interface *intf, pm_message_t msg)
{
struct usb_driver *driver;
Expand Down Expand Up @@ -815,7 +815,7 @@ static int suspend_interface(struct usb_interface *intf, pm_message_t msg)
return status;
}

/* Caller has locked intf */
/* Caller has locked intf's usb_device */
static int resume_interface(struct usb_interface *intf)
{
struct usb_driver *driver;
Expand Down Expand Up @@ -856,25 +856,72 @@ static int resume_interface(struct usb_interface *intf)
return 0;
}

/* Caller has locked udev */
int usb_suspend_both(struct usb_device *udev, pm_message_t msg)
{
int status = 0;
int i = 0;
struct usb_interface *intf;

if (udev->actconfig) {
for (; i < udev->actconfig->desc.bNumInterfaces; i++) {
intf = udev->actconfig->interface[i];
status = suspend_interface(intf, msg);
if (status != 0)
break;
}
}
if (status == 0)
status = suspend_device(udev, msg);

/* If the suspend failed, resume interfaces that did get suspended */
if (status != 0) {
while (--i >= 0) {
intf = udev->actconfig->interface[i];
resume_interface(intf);
}
}
return status;
}

/* Caller has locked udev */
int usb_resume_both(struct usb_device *udev)
{
int status;
int i;
struct usb_interface *intf;

status = resume_device(udev);
if (status == 0 && udev->actconfig) {
for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
intf = udev->actconfig->interface[i];
resume_interface(intf);
}
}
return status;
}

static int usb_suspend(struct device *dev, pm_message_t message)
{
int status;

if (is_usb_device(dev))
status = suspend_device(to_usb_device(dev), message);
status = usb_suspend_both(to_usb_device(dev), message);
else
status = suspend_interface(to_usb_interface(dev), message);
status = 0;
return status;
}

static int usb_resume(struct device *dev)
{
int status;

if (is_usb_device(dev))
status = resume_device(to_usb_device(dev));
else
status = resume_interface(to_usb_interface(dev));
if (is_usb_device(dev)) {
status = usb_resume_both(to_usb_device(dev));

/* Rebind drivers that had no suspend method? */
} else
status = 0;
return status;
}

Expand Down
14 changes: 0 additions & 14 deletions drivers/usb/core/generic.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -184,22 +184,8 @@ static void generic_disconnect(struct usb_device *udev)

#ifdef CONFIG_PM

static int verify_suspended(struct device *dev, void *unused)
{
if (dev->driver == NULL)
return 0;
return (dev->power.power_state.event == PM_EVENT_ON) ? -EBUSY : 0;
}

static int generic_suspend(struct usb_device *udev, pm_message_t msg)
{
int status;

/* rule out bogus requests through sysfs */
status = device_for_each_child(&udev->dev, NULL, verify_suspended);
if (status)
return status;

/* USB devices enter SUSPEND state through their hubs, but can be
* marked for FREEZE as soon as their children are already idled.
* But those semantics are useless, so we equate the two (sigh).
Expand Down
96 changes: 13 additions & 83 deletions drivers/usb/core/hub.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1662,9 +1662,6 @@ static int finish_port_resume(struct usb_device *udev)
"gone after usb resume? status %d\n",
status);
else if (udev->actconfig) {
unsigned i;
int (*resume)(struct device *);

le16_to_cpus(&devstatus);
if ((devstatus & (1 << USB_DEVICE_REMOTE_WAKEUP))
&& udev->parent) {
Expand All @@ -1675,24 +1672,9 @@ static int finish_port_resume(struct usb_device *udev)
USB_DEVICE_REMOTE_WAKEUP, 0,
NULL, 0,
USB_CTRL_SET_TIMEOUT);
if (status) {
if (status)
dev_dbg(&udev->dev, "disable remote "
"wakeup, status %d\n", status);
status = 0;
}
}

/* resume interface drivers; if this is a hub, it
* may have a child resume event to deal with soon
*/
resume = udev->dev.bus->resume;
for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
struct device *dev =
&udev->actconfig->interface[i]->dev;

down(&dev->sem);
(void) resume(dev);
up(&dev->sem);
}
status = 0;

Expand Down Expand Up @@ -1802,15 +1784,7 @@ int usb_port_resume(struct usb_device *udev)
} else
status = finish_port_resume(udev);
if (status < 0)
dev_dbg(&udev->dev, "can't resume, status %d\n",
status);

/* rebind drivers that had no suspend() */
if (status == 0) {
usb_unlock_device(udev);
bus_rescan_devices(&usb_bus_type);
usb_lock_device(udev);
}
dev_dbg(&udev->dev, "can't resume, status %d\n", status);
return status;
}

Expand All @@ -1830,6 +1804,9 @@ static int remote_wakeup(struct usb_device *udev)
msleep(10);
status = finish_port_resume(udev);
}

if (status == 0)
usb_resume_both(udev);
usb_unlock_device(udev);
#endif
return status;
Expand Down Expand Up @@ -1901,51 +1878,8 @@ static int hub_resume(struct usb_interface *intf)
}
}

/* tell khubd to look for changes on this hub */
hub_activate(hub);

/* REVISIT: this recursion probably shouldn't exist. Remove
* this code sometime, after retesting with different root and
* external hubs.
*/
#ifdef CONFIG_USB_SUSPEND
{
unsigned port1;

for (port1 = 1; port1 <= hdev->maxchild; port1++) {
struct usb_device *udev;
u16 portstat, portchange;

udev = hdev->children [port1-1];
status = hub_port_status(hub, port1, &portstat, &portchange);
if (status == 0) {
if (portchange & USB_PORT_STAT_C_SUSPEND) {
clear_port_feature(hdev, port1,
USB_PORT_FEAT_C_SUSPEND);
portchange &= ~USB_PORT_STAT_C_SUSPEND;
}

/* let khubd handle disconnects etc */
if (portchange)
continue;
}

if (!udev || status < 0)
continue;
usb_lock_device(udev);
if (portstat & USB_PORT_STAT_SUSPEND)
status = hub_port_resume(hub, port1, udev);
else {
status = finish_port_resume(udev);
if (status < 0) {
dev_dbg(&intf->dev, "resume port %d --> %d\n",
port1, status);
hub_port_logical_disconnect(hub, port1);
}
}
usb_unlock_device(udev);
}
}
#endif
return 0;
}

Expand Down Expand Up @@ -2602,17 +2536,6 @@ static void hub_events(void)
usb_get_intf(intf);
spin_unlock_irq(&hub_event_lock);

/* Is this is a root hub wanting to reactivate the downstream
* ports? If so, be sure the interface resumes even if its
* stub "device" node was never suspended.
*/
if (i) {
dpm_runtime_resume(&hdev->dev);
dpm_runtime_resume(&intf->dev);
usb_put_intf(intf);
continue;
}

/* Lock the device, then check to see if we were
* disconnected while waiting for the lock to succeed. */
if (locktree(hdev) < 0) {
Expand All @@ -2629,6 +2552,13 @@ static void hub_events(void)
goto loop;
}

/* Is this is a root hub wanting to reactivate the downstream
* ports? If so, be sure the interface resumes even if its
* stub "device" node was never suspended.
*/
if (i)
usb_resume_both(hdev);

/* If this is an inactive or suspended hub, do nothing */
if (hub->quiescing)
goto loop;
Expand Down
2 changes: 2 additions & 0 deletions drivers/usb/core/usb.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,8 @@ extern void usb_major_cleanup(void);
extern int usb_host_init(void);
extern void usb_host_cleanup(void);

extern int usb_suspend_both(struct usb_device *udev, pm_message_t msg);
extern int usb_resume_both(struct usb_device *udev);
extern int usb_port_suspend(struct usb_device *dev);
extern int usb_port_resume(struct usb_device *dev);

Expand Down

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