This is a note to let you know that I've just added the patch titled
USB: Reset USB 3.0 devices on (re)discovery
to the 2.6.37-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-reset-usb-3.0-devices-on-re-discovery.patch
and it can be found in the queue-2.6.37 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 07194ab7be63a972096309ab0ea747df455c6a20 Mon Sep 17 00:00:00 2001
From: Luben Tuikov <[email protected]>
Date: Fri, 11 Feb 2011 11:33:10 -0800
Subject: USB: Reset USB 3.0 devices on (re)discovery
From: Luben Tuikov <[email protected]>
commit 07194ab7be63a972096309ab0ea747df455c6a20 upstream.
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 <[email protected]>
Signed-off-by: Sarah Sharp <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/usb/core/hub.c | 18 +++++++-----------
1 file changed, 7 insertions(+), 11 deletions(-)
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2672,17 +2672,13 @@ hub_port_init (struct usb_hub *hub, stru
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) {
Patches currently in stable-queue which might be from [email protected] are
queue-2.6.37/usb-reset-usb-3.0-devices-on-re-discovery.patch
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