[3.16.y-ckt stable] Patch "xhci: Check if slot is already in default state before moving it there" has been added to staging queue

[Luis Henriques]

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

    xhci: Check if slot is already in default state before moving it there

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt5.

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

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 4ecfd6af48e0d211a14ef4d5773f8ba83346b631 Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman at linux.intel.com>
Date: Fri, 9 Jan 2015 17:18:28 +0200
Subject: xhci: Check if slot is already in default state before moving it
 there

commit f161ead70fa6a62e432dff6e9dab8e3cfbeabea6 upstream.

Solves xhci error cases with debug messages:
xhci_hcd 0000:00:14.0: Setup ERROR: setup context command for slot 1.
usb 1-6: hub failed to enable device, error -22

xhci will give a context state error if we try to set a slot in default
state to the same default state with a special address device command.

Turns out this happends in several cases:
- retry reading the device rescriptor in hub_port_init()
- usb_reset_device() is called for a slot in default state
- in resume path, usb_port_resume() calls hub_port_init()

The default state is usually reached from most states with a reset device
command without any context state errors, but using the address device
command with BSA bit set (block set address) only works from the enabled
state and will otherwise cause context error.

solve this by checking if we are already in the default state before issuing
a address device BSA=1 command.

Fixes: 48fc7dbd52c0 ("usb: xhci: change enumeration scheme to 'new scheme'")
Signed-off-by: Mathias Nyman <mathias.nyman at linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/usb/host/xhci.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 5e5f0c1b6613..b61913116fe2 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -3812,6 +3812,15 @@ static int xhci_setup_device(struct usb_hcd *hcd, struct usb_device *udev,
 		return -EINVAL;
 	}

+	if (setup == SETUP_CONTEXT_ONLY) {
+		slot_ctx = xhci_get_slot_ctx(xhci, virt_dev->out_ctx);
+		if (GET_SLOT_STATE(le32_to_cpu(slot_ctx->dev_state)) ==
+		    SLOT_STATE_DEFAULT) {
+			xhci_dbg(xhci, "Slot already in default state\n");
+			return 0;
+		}
+	}
+
 	command = xhci_alloc_command(xhci, false, false, GFP_KERNEL);
 	if (!command)
 		return -ENOMEM;
--
2.1.4