USB: implement usb_enable_autosuspend
This patch (as1326) adds usb_enable_autosuspend() and
usb_disable_autosuspend() routines for use by drivers. If a driver
knows that its device can handle suspends and resumes correctly, it
can enable autosuspend all by itself. This is equivalent to the user
writing "auto" to the device's power/level attribute.
The implementation differs slightly from what it used to be. Now
autosuspend is disabled simply by doing usb_autoresume_device() (to
increment the usage counter) and enabled by doing
usb_autosuspend_device() (to decrement the usage counter).
The set_level() attribute method is updated to use the new routines,
and the USB Power-Management documentation is updated.
The patch adds a usb_enable_autosuspend() call to the hub driver's
probe routine, allowing the special-case code for hubs in quirks.c to
be removed.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index 5a1a0e2..313e241 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -389,34 +389,25 @@
struct usb_device *udev = to_usb_device(dev);
int len = count;
char *cp;
- int rc = 0;
- int old_autosuspend_disabled;
+ int rc;
cp = memchr(buf, '\n', count);
if (cp)
len = cp - buf;
usb_lock_device(udev);
- old_autosuspend_disabled = udev->autosuspend_disabled;
- /* Setting the flags without calling usb_pm_lock is a subject to
- * races, but who cares...
- */
if (len == sizeof on_string - 1 &&
- strncmp(buf, on_string, len) == 0) {
- udev->autosuspend_disabled = 1;
- rc = usb_external_resume_device(udev, PMSG_USER_RESUME);
+ strncmp(buf, on_string, len) == 0)
+ rc = usb_disable_autosuspend(udev);
- } else if (len == sizeof auto_string - 1 &&
- strncmp(buf, auto_string, len) == 0) {
- udev->autosuspend_disabled = 0;
- rc = usb_external_resume_device(udev, PMSG_USER_RESUME);
+ else if (len == sizeof auto_string - 1 &&
+ strncmp(buf, auto_string, len) == 0)
+ rc = usb_enable_autosuspend(udev);
- } else
+ else
rc = -EINVAL;
- if (rc)
- udev->autosuspend_disabled = old_autosuspend_disabled;
usb_unlock_device(udev);
return (rc < 0 ? rc : count);
}