[PATCH 104/106] usb: Clear both buffers when clearing a control transfer TT buffer.

[Luis Henriques]

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

------------------

From: William Gulland <wgulland at google.com>

commit 2c7b871b9102c497ba8f972aa5d38532f05b654d upstream.

Control transfers have both IN and OUT (or SETUP) packets, so when
clearing TT buffers for a control transfer it's necessary to send
two HUB_CLEAR_TT_BUFFER requests to the hub.

Signed-off-by: William Gulland <wgulland at google.com>
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 | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 9d70788..d5515c0 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -710,6 +710,15 @@ resubmit:
 static inline int
 hub_clear_tt_buffer (struct usb_device *hdev, u16 devinfo, u16 tt)
 {
+	/* Need to clear both directions for control ep */
+	if (((devinfo >> 11) & USB_ENDPOINT_XFERTYPE_MASK) ==
+			USB_ENDPOINT_XFER_CONTROL) {
+		int status = usb_control_msg(hdev, usb_sndctrlpipe(hdev, 0),
+				HUB_CLEAR_TT_BUFFER, USB_RT_PORT,
+				devinfo ^ 0x8000, tt, NULL, 0, 1000);
+		if (status)
+			return status;
+	}
 	return usb_control_msg(hdev, usb_sndctrlpipe(hdev, 0),
 			       HUB_CLEAR_TT_BUFFER, USB_RT_PORT, devinfo,
 			       tt, NULL, 0, 1000);
-- 
1.8.3.2