[PATCH 3.16.y-ckt 040/128] USB: add quirk for devices with broken LPM

[Luis Henriques]

3.16.7-ckt23 -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>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@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 882acb2a0b48..a1e577777a02 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -128,6 +128,10 @@ 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.
 	 */
@@ -4479,6 +4483,8 @@ 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) {
@@ -4674,7 +4680,6 @@ 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 2b978ad9d9ef..0e8e656a045f 100644
--- a/drivers/usb/core/quirks.c
+++ b/drivers/usb/core/quirks.c
@@ -188,6 +188,12 @@ static const struct usb_device_id usb_quirk_list[] = {
 	/* USB3503 */
 	{ USB_DEVICE(0x0424, 0x3503), .driver_info = USB_QUIRK_RESET_RESUME },
 
+	/* 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 4a185a0f6242..8f4f2214652f 100644
--- a/include/linux/usb/quirks.h
+++ b/include/linux/usb/quirks.h
@@ -47,4 +47,7 @@
 /* device can't handle device_qualifier descriptor requests */
 #define USB_QUIRK_DEVICE_QUALIFIER	0x00000100
 
+/* device can't handle Link Power Management */
+#define USB_QUIRK_NO_LPM			BIT(10)
+
 #endif /* __LINUX_USB_QUIRKS_H */