[PATCH 3.16 115/125] usb: hub: Prevent hub autosuspend if usbcore.autosuspend is -1

[Greg Kroah-Hartman]

3.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Roger Quadros <rogerq@xxxxxx>

commit bdd405d2a5287bdb9b04670ea255e1f122138e66 upstream.

If user specifies that USB autosuspend must be disabled by module
parameter "usbcore.autosuspend=-1" then we must prevent
autosuspend of USB hub devices as well.

commit 596d789a211d introduced in v3.8 changed the original behaivour
and stopped respecting the usbcore.autosuspend parameter for hubs.

Fixes: 596d789a211d "USB: set hub's default autosuspend delay as 0"

Signed-off-by: Roger Quadros <rogerq@xxxxxx>
Tested-by: Michael Welling <mwelling@xxxxxxxxxxx>
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/usb/core/hub.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1728,8 +1728,12 @@ static int hub_probe(struct usb_interfac
 	 * - Change autosuspend delay of hub can avoid unnecessary auto
 	 *   suspend timer for hub, also may decrease power consumption
 	 *   of USB bus.
+	 *
+	 * - If user has indicated to prevent autosuspend by passing
+	 *   usbcore.autosuspend = -1 then keep autosuspend disabled.
 	 */
-	pm_runtime_set_autosuspend_delay(&hdev->dev, 0);
+	if (hdev->dev.power.autosuspend_delay >= 0)
+		pm_runtime_set_autosuspend_delay(&hdev->dev, 0);
 
 	/*
 	 * Hubs have proper suspend/resume support, except for root hubs


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