From: Luben Tuikov <ltuikov@yahoo.com>
Date: Fri, 11 Feb 2011 19:33:10 +0000 (-0800)
Subject: USB: Reset USB 3.0 devices on (re)discovery
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=07194ab7be63a972096309ab0ea747df455c6a20;p=linux-beck.git

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.

Note from Sarah Sharp:

This patch should be queued for stable trees all the way back to 2.6.34,
since that was the first kernel that supported configured device reset.
The code this patch touches has been there since 2.6.32, but the bug
would never be hit before 2.6.34 because the xHCI driver would
completely reject an attempt to reset a configured device under xHCI.

Signed-off-by: Luben Tuikov <ltuikov@yahoo.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@kernel.org
---

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index d041c6826e43..0f299b7aad60 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -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 */
-	}
+	/* 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) {