[PATCH v2] usb: hub: Prevent hub autosuspend if usbcore.autosuspend is -1

[Roger Quadros <rogerq@ti.com>]

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"

Cc: [3.8+] <stable@vger.kernel.org>
Signed-off-by: Roger Quadros <rogerq@ti.com>
---
 drivers/usb/core/hub.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 8a4dcbc..59b599d 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1728,8 +1728,14 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
 	 * - 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);
+#ifdef CONFIG_PM_RUNTIME
+	if (hdev->dev.power.autosuspend_delay >= 0)
+		pm_runtime_set_autosuspend_delay(&hdev->dev, 0);
+#endif
 
 	/*
 	 * Hubs have proper suspend/resume support, except for root hubs
-- 
1.8.3.2