USB: Fix USB3.0 Port Speed Downgrade after port reset
Sarah Sharp [Fri, 9 Jul 2010 15:08:48 +0000 (17:08 +0200)]
Without this fix, a USB 3.0 port is downgraded to full speed after a port
reset of a configured device.  The USB 3.0 terminations will be disabled
permanently, and USB 3.0 devices will always enumerate as full speed
devices, until the host controller is unplugged (if it is an ExpressCard)
or the computer is rebooted.

Fajun Chen traced this traced the speed downgrade issue to the port reset
and the interpretation of port status in USB hub driver code.  The hub
code was not testing for the port being a SuperSpeed port, and it fell
through to the else case of Full Speed.

The following patch adds SuperSpeed mapping from the port status, and
fixes the speed downgrade issue.

Reported-by: Fajun Chen <fajun.chen@seagate.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/hub.c

index 83e7bbb..70cccc7 100644 (file)
@@ -1982,6 +1982,8 @@ static int hub_port_wait_reset(struct usb_hub *hub, int port1,
                    (portstatus & USB_PORT_STAT_ENABLE)) {
                        if (hub_is_wusb(hub))
                                udev->speed = USB_SPEED_WIRELESS;
+                       else if (portstatus & USB_PORT_STAT_SUPER_SPEED)
+                               udev->speed = USB_SPEED_SUPER;
                        else if (portstatus & USB_PORT_STAT_HIGH_SPEED)
                                udev->speed = USB_SPEED_HIGH;
                        else if (portstatus & USB_PORT_STAT_LOW_SPEED)