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USB: skip autosuspended devices during system resume 

System suspends and hibernation are supposed to be as transparent as
possible.  By this reasoning, if a USB device is already autosuspended
before the system sleep begins then it should remain autosuspended
after the system wakes up.

This patch (as1001) adds a skip_sys_resume flag to the usb_device
structure and uses it to avoid waking up devices which were suspended
when a system sleep began.

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 2007-10-10 16:30:12 -04:00 committed by Greg Kroah-Hartman
parent 32fe01985a
commit 271f9e68f3
2 changed files with 21 additions and 7 deletions
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27
drivers/usb/core/driver.c
View File

@ -1540,9 +1540,21 @@ int usb_external_resume_device(struct usb_device *udev)
static int usb_suspend(struct device *dev, pm_message_t message)
{
struct usb_device *udev;
if (!is_usb_device(dev)) /* Ignore PM for interfaces */
return 0;
return usb_external_suspend_device(to_usb_device(dev), message);
udev = to_usb_device(dev);
/* If udev is already suspended, we can skip this suspend and
* we should also skip the upcoming system resume. */
if (udev->state == USB_STATE_SUSPENDED) {
udev->skip_sys_resume = 1;
return 0;
}
udev->skip_sys_resume = 0;
return usb_external_suspend_device(udev, message);
}
static int usb_resume(struct device *dev)
@ -1553,13 +1565,14 @@ static int usb_resume(struct device *dev)
return 0;
udev = to_usb_device(dev);
/* If autoresume is disabled then we also want to prevent resume
* during system wakeup. However, a "persistent-device" reset-resume
* after power loss counts as a wakeup event. So allow a
* reset-resume to occur if remote wakeup is enabled. */
if (udev->autoresume_disabled) {
/* If udev->skip_sys_resume is set then udev was already suspended
* when the system suspend started, so we don't want to resume
* udev during this system wakeup. However a reset-resume counts
* as a wakeup event, so allow a reset-resume to occur if remote
* wakeup is enabled. */
if (udev->skip_sys_resume) {
if (!(udev->reset_resume && udev->do_remote_wakeup))
return -EPERM;
return -EHOSTUNREACH;
}
return usb_external_resume_device(udev);
}

1
include/linux/usb.h
View File

@ -430,6 +430,7 @@ struct usb_device {
unsigned persist_enabled:1; /* USB_PERSIST enabled for this dev */
unsigned autosuspend_disabled:1; /* autosuspend and autoresume */
unsigned autoresume_disabled:1; /* disabled by the user */
unsigned skip_sys_resume:1; /* skip the next system resume */
#endif
};
#define to_usb_device(d) container_of(d, struct usb_device, dev)