USB: make autosuspend delay a module parameter

This patch (as859) makes the default USB autosuspend delay a module
parameter of usbcore.  By setting the delay value at boot time, users
will be able to prevent the system from autosuspending devices which
for some reason can't handle it.

The patch also stores the autosuspend delay as a per-device value.  A
later patch will allow the user to change the value, tailoring the
delay for each individual device.  A delay value of 0 will prevent
autosuspend.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 10 insertions, 6 deletions

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index f9196a0a9412..a420d72a0254 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -963,12 +963,16 @@ static int autosuspend_check(struct usb_device *udev)
         int                     i;
         struct usb_interface    *intf;
 
-        /* For autosuspend, fail fast if anything is in use.
-         * Also fail if any interfaces require remote wakeup but it
-         * isn't available. */
+        /* For autosuspend, fail fast if anything is in use or autosuspend
+         * is disabled.  Also fail if any interfaces require remote wakeup
+         * but it isn't available.
+         */
         udev->do_remote_wakeup = device_may_wakeup(&udev->dev);
         if (udev->pm_usage_cnt > 0)
                 return -EBUSY;
+        if (!udev->autosuspend_delay)
+                return -EPERM;
+
         if (udev->actconfig) {
                 for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
                         intf = udev->actconfig->interface[i];
@@ -991,7 +995,7 @@ static int autosuspend_check(struct usb_device *udev)
 
 #define autosuspend_check(udev)         0
 
-#endif
+#endif  /* CONFIG_USB_SUSPEND */
 
 /**
  * usb_suspend_both - suspend a USB device and its interfaces
@@ -1186,7 +1190,7 @@ static int usb_autopm_do_device(struct usb_device *udev, int inc_usage_cnt)
                         udev->pm_usage_cnt -= inc_usage_cnt;
         } else if (inc_usage_cnt <= 0 && autosuspend_check(udev) == 0)
                 queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,
-                                USB_AUTOSUSPEND_DELAY);
+                                udev->autosuspend_delay);
         usb_pm_unlock(udev);
         return status;
 }
@@ -1270,7 +1274,7 @@ static int usb_autopm_do_interface(struct usb_interface *intf,
                                 intf->pm_usage_cnt -= inc_usage_cnt;
                 } else if (inc_usage_cnt <= 0 && autosuspend_check(udev) == 0)
                         queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,
-                                        USB_AUTOSUSPEND_DELAY);
+                                        udev->autosuspend_delay);
         }
         usb_pm_unlock(udev);
         return status;