[3.11.y.z extended stable] Patch "usb: hub: Clear Port Reset Change during init/resume" has been added to staging queue

Luis Henriques luis.henriques at canonical.com
Thu Dec 5 11:25:51 UTC 2013


This is a note to let you know that I have just added a patch titled

    usb: hub: Clear Port Reset Change during init/resume

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From e791e1b6710fb4c99ac8bd9c803cf5835b5fbe58 Mon Sep 17 00:00:00 2001
From: Julius Werner <jwerner at chromium.org>
Date: Tue, 15 Oct 2013 17:45:00 -0700
Subject: usb: hub: Clear Port Reset Change during init/resume

commit e92aee330837e4911553761490a8fb843f2053a6 upstream.

This patch adds the Port Reset Change flag to the set of bits that are
preemptively cleared on init/resume of a hub. In theory this bit should
never be set unexpectedly... in practice it can still happen if BIOS,
SMM or ACPI code plays around with USB devices without cleaning up
correctly. This is especially dangerous for XHCI root hubs, which don't
generate any more Port Status Change Events until all change bits are
cleared, so this is a good precaution to have (similar to how it's
already done for the Warm Port Reset Change flag).

Signed-off-by: Julius Werner <jwerner at chromium.org>
Acked-by: Alan Stern <stern at rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/usb/core/hub.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index ef15a22..9ba5fcd4 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1129,6 +1129,11 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
 			usb_clear_port_feature(hub->hdev, port1,
 					USB_PORT_FEAT_C_ENABLE);
 		}
+		if (portchange & USB_PORT_STAT_C_RESET) {
+			need_debounce_delay = true;
+			usb_clear_port_feature(hub->hdev, port1,
+					USB_PORT_FEAT_C_RESET);
+		}
 		if ((portchange & USB_PORT_STAT_C_BH_RESET) &&
 				hub_is_superspeed(hub->hdev)) {
 			need_debounce_delay = true;
--
1.8.3.2





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