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 <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 14 insertions, 2 deletions

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index f936de75f44..e68fef5361d 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -129,7 +129,7 @@ static const u8 usb2_rh_dev_descriptor [18] = {
 
         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 */
@@ -354,9 +354,10 @@ static int rh_call_control (struct usb_hcd *hcd, struct urb *urb)
                 __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();
 
@@ -433,6 +434,8 @@ static int rh_call_control (struct usb_hcd *hcd, struct urb *urb)
                         else
                                 goto error;
                         len = 18;
+                        if (hcd->has_tt)
+                                patch_protocol = 1;
                         break;
                 case USB_DT_CONFIG << 8:
                         if (hcd->driver->flags & HCD_USB2) {
@@ -527,6 +530,13 @@ error:
                                                 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 */
diff --git a/drivers/usb/core/hcd.h b/drivers/usb/core/hcd.h
index 2c086b8460b..e0e99471c3f 100644
--- a/drivers/usb/core/hcd.h
+++ b/drivers/usb/core/hcd.h
@@ -99,6 +99,7 @@ struct usb_hcd {
         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 */
diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c
index 040bd8632eb..7c8a2ccf78f 100644
--- a/drivers/usb/host/ehci-pci.c
+++ b/drivers/usb/host/ehci-pci.c
@@ -130,6 +130,7 @@ static int ehci_pci_setup(struct usb_hcd *hcd)
         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;