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>
diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 3f73424..8c1eac2 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -1540,9 +1540,21 @@
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 @@
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);
}