Commit 637d11bf authored Feb 11, 2011 by Luben Tuikov Committed by Greg Kroah-Hartman Feb 17, 2011

USB: Reset USB 3.0 devices on (re)discovery



If the device isn't reset, the XHCI HCD sends
SET ADDRESS to address 0 while the device is
already in Addressed state, and the request is
dropped on the floor as it is addressed to the
default address. This sequence of events, which this
patch fixes looks like this:

usb_reset_and_verify_device()
	hub_port_init()
		hub_set_address()
			SET_ADDRESS to 0 with 1
		usb_get_device_descriptor(udev, 8)
		usb_get_device_descriptor(udev, 18)
	descriptors_changed() --> goto re_enumerate:
		hub_port_logical_disconnect()
			kick_khubd()

And then:

hub_events()
	hub_port_connect_change()
		usb_disconnect()
			usb_disable_device()
		new device struct
		sets device state to Powered
		choose_address()
		hub_port_init() <-- no reset, but SET ADDRESS to 0 with 1, timeout!

The solution is to always reset the device in
hub_port_init() to put it in a known state.

Signed-off-by: Luben Tuikov <ltuikov@yahoo.com>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

parent 72a012ce

drivers/usb/core/hub.c

+7 −11

Original line number	Diff line number	Diff line
		@@ -2681,17 +2681,13 @@ hub_port_init (struct usb_hub hub, struct usb_device udev, int port1,

		mutex_lock(&usb_address0_mutex);

		if (!udev->config && oldspeed == USB_SPEED_SUPER) {
		/* Don't reset USB 3.0 devices during an initial setup */
		usb_set_device_state(udev, USB_STATE_DEFAULT);
		} else {
		/* Reset the device; full speed may morph to high speed */
		/* FIXME a USB 2.0 device may morph into SuperSpeed on reset. */
		retval = hub_port_reset(hub, port1, udev, delay);
		if (retval < 0) /* error or disconnect */
		goto fail;
		/* success, speed is known */
		}

		retval = -ENODEV;

		if (oldspeed != USB_SPEED_UNKNOWN && oldspeed != udev->speed) {

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