xhci: Don't let the USB core disable SuperSpeed ports.

commit 6dd0a3a7e0793dbeae1b951f091025d8cf896cb4 upstream.

Disabling SuperSpeed ports is a Very Bad Thing (TM).  It disables
SuperSpeed terminations, which means that devices will never connect at
SuperSpeed on that port.  For USB 2.0/1.1 ports, disabling the port meant
that the USB core could always get a connect status change later.  That's
not true with USB 3.0 ports.

Do not let the USB core disable SuperSpeed ports.  We can't rely on the
device speed in the port status registers, since that isn't valid until
there's a USB device connected to the port.  Instead, we use the port
speed array that's created from the Extended Capabilities registers.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Tested-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index a1a7a9795536c6c2bae9bb4a08f852cd9719cd57..480936a870ce86da6835cc00fcd0b06b8d8164f8 100644 (file)
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -132,6 +132,13 @@ static u32 xhci_port_state_to_neutral(u32 state)
 static void xhci_disable_port(struct xhci_hcd *xhci, u16 wIndex,
                u32 __iomem *addr, u32 port_status)
 {
+       /* Don't allow the USB core to disable SuperSpeed ports. */
+       if (xhci->port_array[wIndex] == 0x03) {
+               xhci_dbg(xhci, "Ignoring request to disable "
+                               "SuperSpeed port.\n");
+               return;
+       }
+
        /* Write 1 to disable the port */
        xhci_writel(xhci, port_status | PORT_PE, addr);
        port_status = xhci_readl(xhci, addr);