[linux-usb-devel] [PATCH 2.6.6] khubd turns port power back on after reset

[David Brownell]

This goes with the OHCI anti-deadlock patch, and is what
ensures that when a root hub loses power during suspend,
khubd can turn port power back on so devices can enumerate.
- Dave

--- bk2/xu26/drivers/usb/core/hub.c     2004-05-06 07:46:43.000000000 -0700
+++ gadget-2.6/drivers/usb/core/hub.c   2004-05-09 10:26:14.000000000 -0700
@@ -1282,9 +1777,16 @@
        /* Disconnect any existing devices under this port */
        if (hub->children[port])
                usb_disconnect(&hub->children[port]);
- 
+
        /* Return now if nothing is connected */
        if (!(portstatus & USB_PORT_STAT_CONNECTION)) {
+
+               /* maybe switch power back on (e.g. root hub was reset) */
+               if ((hubstate->descriptor->wHubCharacteristics
+                                       & HUB_CHAR_LPSM) < 2
+                               && !(portstatus & (1 << USB_PORT_FEAT_POWER)))
+                       set_port_feature(hub, port + 1, USB_PORT_FEAT_POWER);
+ 
                if (portstatus & USB_PORT_STAT_ENABLE)
                        goto done;
                return;