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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>
This commit is contained in:
Alan Stern 2006-07-01 22:11:02 -04:00 committed by Greg Kroah-Hartman
parent 1cc8a25d5b
commit a8e7c56535
4 changed files with 70 additions and 105 deletions
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63
drivers/usb/core/driver.c
View file

@ -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;
@ -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;
@ -856,14 +856,59 @@ 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;
}
@ -871,10 +916,12 @@ 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;
}

14
drivers/usb/core/generic.c
View file

@ -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).

96
drivers/usb/core/hub.c
View file

@ -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) {
@ -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;
@ -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;
}
@ -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;
@ -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;
}
@ -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) {
@ -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;

2
drivers/usb/core/usb.h
View file

@ -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);