[PATCH] USB: relax usbcore reset timings

This appears to help some folk, please merge.
This patch relaxes reset timings.  There are some reports that it
helps make enumeration work better on some high speed devices.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index c55208299cf85cb93d1669aa0feb32ec35c1eb27..a12cab5314e98720fb87b78c05a542789c53f395 100644 (file)
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -435,6 +435,7 @@ void usb_hub_tt_clear_buffer (struct usb_device *udev, int pipe)
 static void hub_power_on(struct usb_hub *hub)
 {
        int port1;
+       unsigned pgood_delay = hub->descriptor->bPwrOn2PwrGood * 2;
 
        /* if hub supports power switching, enable power on each port */
        if ((hub->descriptor->wHubCharacteristics & HUB_CHAR_LPSM) < 2) {
@@ -444,8 +445,8 @@ static void hub_power_on(struct usb_hub *hub)
                                        USB_PORT_FEAT_POWER);
        }
 
-       /* Wait for power to be enabled */
-       msleep(hub->descriptor->bPwrOn2PwrGood * 2);
+       /* Wait at least 100 msec for power to become stable */
+       msleep(max(pgood_delay, (unsigned) 100));
 }
 
 static void hub_quiesce(struct usb_hub *hub)
@@ -1469,8 +1470,8 @@ static int hub_port_reset(struct usb_hub *hub, int port1,
                /* return on disconnect or reset */
                switch (status) {
                case 0:
-                       /* TRSTRCY = 10 ms */
-                       msleep(10);
+                       /* TRSTRCY = 10 ms; plus some extra */
+                       msleep(10 + 40);
                        /* FALL THROUGH */
                case -ENOTCONN:
                case -ENODEV: