[PATCH 4.2.y-ckt 174/305] USB: add quirk for devices with broken LPM

[Kamal Mostafa]

4.2.8-ckt2 -stable review patch.  If anyone has any objections, please let me know.

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

From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxxxxxx>
Reported-by: Steinar H. Gunderson <sgunderson@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
 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 253b08b..5eb29e8 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -124,6 +124,10 @@ struct usb_hub *usb_hub_to_struct_hub(struct usb_device *hdev)
 
 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.
 	 */
@@ -4499,6 +4503,8 @@ 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) {
@@ -4697,7 +4703,6 @@ static void hub_port_connect(struct usb_hub *hub, int port1, u16 portstatus,
 		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 f5a3819..017c1de 100644
--- a/drivers/usb/core/quirks.c
+++ b/drivers/usb/core/quirks.c
@@ -199,6 +199,12 @@ static const struct usb_device_id usb_quirk_list[] = {
 	{ USB_DEVICE(0x1a0a, 0x0200), .driver_info =
 			USB_QUIRK_LINEAR_UFRAME_INTR_BINTERVAL },
 
+	/* 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 9948c87..1d0043d 100644
--- a/include/linux/usb/quirks.h
+++ b/include/linux/usb/quirks.h
@@ -47,4 +47,7 @@
 /* device generates spurious wakeup, ignore remote wakeup capability */
 #define USB_QUIRK_IGNORE_REMOTE_WAKEUP		BIT(9)
 
+/* device can't handle Link Power Management */
+#define USB_QUIRK_NO_LPM			BIT(10)
+
 #endif /* __LINUX_USB_QUIRKS_H */
-- 
1.9.1