USB: root hubs don't lie about their number of TTs

Currently EHCI root hubs enumerate with a bDeviceProtocol code
indicating that they possess a Transaction Translator. However the
vast majority of controllers do not; they rely on a companion
controller to handle full- and low-speed communications. This patch
(as1064) changes the root-hub device descriptor to match the actual
situation.

Signed-off-by: Alan Stern <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/core/hcd.c

···
 
 	0x09,	    /*  __u8  bDeviceClass; HUB_CLASSCODE */
 	0x00,	    /*  __u8  bDeviceSubClass; */
-	0x01,       /*  __u8  bDeviceProtocol; [ usb 2.0 single TT ]*/
+	0x00,       /*  __u8  bDeviceProtocol; [ usb 2.0 no TT ] */
 	0x40,       /*  __u8  bMaxPacketSize0; 64 Bytes */
 
 	0x6b, 0x1d, /*  __le16 idVendor; Linux Foundation */
···
 		__attribute__((aligned(4)));
 	const u8	*bufp = tbuf;
 	int		len = 0;
-	int		patch_wakeup = 0;
 	int		status;
 	int		n;
+	u8		patch_wakeup = 0;
+	u8		patch_protocol = 0;
 
 	might_sleep();
 
···
 			else
 				goto error;
 			len = 18;
+			if (hcd->has_tt)
+				patch_protocol = 1;
 			break;
 		case USB_DT_CONFIG << 8:
 			if (hcd->driver->flags & HCD_USB2) {
···
 						bmAttributes))
 			((struct usb_config_descriptor *)ubuf)->bmAttributes
 				|= USB_CONFIG_ATT_WAKEUP;
+
+		/* report whether RH hardware has an integrated TT */
+		if (patch_protocol &&
+				len > offsetof(struct usb_device_descriptor,
+						bDeviceProtocol))
+			((struct usb_device_descriptor *) ubuf)->
+					bDeviceProtocol = 1;
 	}
 
 	/* any errors get returned through the urb completion */

drivers/usb/core/hcd.h

···
 	unsigned		poll_pending:1;	/* status has changed? */
 	unsigned		wireless:1;	/* Wireless USB HCD */
 	unsigned		authorized_default:1;
+	unsigned		has_tt:1;	/* Integrated TT in root hub */
 
 	int			irq;		/* irq allocated */
 	void __iomem		*regs;		/* device memory/io */

drivers/usb/host/ehci-pci.c

···
 	case PCI_VENDOR_ID_TDI:
 		if (pdev->device == PCI_DEVICE_ID_TDI_EHCI) {
 			ehci->is_tdi_rh_tt = 1;
+			hcd->has_tt = 1;
 			tdi_reset(ehci);
 		}
 		break;