[3.13.y-ckt stable] Patch "USB: add quirk for devices with broken LPM" has been added to the 3.13.y-ckt tree

[Kamal Mostafa]

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

    USB: add quirk for devices with broken LPM

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt33.

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

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 89dd60927de7bbd337cdb77440a10a843f422d1f Mon Sep 17 00:00:00 2001
From: Alan Stern <stern at rowland.harvard.edu>
Date: Thu, 10 Dec 2015 15:27:21 -0500
Subject: USB: add quirk for devices with broken LPM

commit ad87e03213b552a5c33d5e1e7a19a73768397010 upstream.

Some USB device / host controller combinations seem to have problems
with Link Power Management.  For example, Steinar found that his xHCI
controller wouldn't handle bandwidth calculations correctly for two
video cards simultaneously when LPM was enabled, even though the bus
had plenty of bandwidth available.

This patch introduces a new quirk flag for devices that should remain
disabled for LPM, and creates quirk entries for Steinar's devices.

Signed-off-by: Alan Stern <stern at rowland.harvard.edu>
Reported-by: Steinar H. Gunderson <sgunderson at bigfoot.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/usb/core/hub.c     | 7 ++++++-
 drivers/usb/core/quirks.c  | 6 ++++++
 include/linux/usb/quirks.h | 3 +++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index f568236..ab6b128 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -137,6 +137,10 @@ struct usb_hub *usb_hub_to_struct_hub(struct usb_device *hdev)

 static int usb_device_supports_lpm(struct usb_device *udev)
 {
+	/* Some devices have trouble with LPM */
+	if (udev->quirks & USB_QUIRK_NO_LPM)
+		return 0;
+
 	/* USB 2.1 (and greater) devices indicate LPM support through
 	 * their USB 2.0 Extended Capabilities BOS descriptor.
 	 */
@@ -4298,6 +4302,8 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
 		goto fail;
 	}

+	usb_detect_quirks(udev);
+
 	if (udev->wusb == 0 && le16_to_cpu(udev->descriptor.bcdUSB) >= 0x0201) {
 		retval = usb_get_bos_descriptor(udev);
 		if (!retval) {
@@ -4540,7 +4546,6 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
 		if (status < 0)
 			goto loop;

-		usb_detect_quirks(udev);
 		if (udev->quirks & USB_QUIRK_DELAY_INIT)
 			msleep(1000);

diff --git a/drivers/usb/core/quirks.c b/drivers/usb/core/quirks.c
index 7409a4d..f308a88 100644
--- a/drivers/usb/core/quirks.c
+++ b/drivers/usb/core/quirks.c
@@ -175,6 +175,12 @@ static const struct usb_device_id usb_quirk_list[] = {
 	{ USB_DEVICE(0x0b05, 0x17e0), .driver_info =
 			USB_QUIRK_IGNORE_REMOTE_WAKEUP },

+	/* Blackmagic Design Intensity Shuttle */
+	{ USB_DEVICE(0x1edb, 0xbd3b), .driver_info = USB_QUIRK_NO_LPM },
+
+	/* Blackmagic Design UltraStudio SDI */
+	{ USB_DEVICE(0x1edb, 0xbd4f), .driver_info = USB_QUIRK_NO_LPM },
+
 	{ }  /* terminating entry must be last */
 };

diff --git a/include/linux/usb/quirks.h b/include/linux/usb/quirks.h
index 49587dc..41ea53c 100644
--- a/include/linux/usb/quirks.h
+++ b/include/linux/usb/quirks.h
@@ -33,4 +33,7 @@
 /* device generates spurious wakeup, ignore remote wakeup capability */
 #define USB_QUIRK_IGNORE_REMOTE_WAKEUP	0x00000200

+/* device can't handle Link Power Management */
+#define USB_QUIRK_NO_LPM			BIT(10)
+
 #endif /* __LINUX_USB_QUIRKS_H */
--
1.9.1