xhci: Enable LPM support only for hardwired or BESL devices

[cascardo/linux.git] / drivers / usb / core / hub.c

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 9be1a2d..566ac55 100644 (file)
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -3953,6 +3953,32 @@ static int hub_set_address(struct usb_device *udev, int devnum)
        return retval;
 }
 
+/*
+ * There are reports of USB 3.0 devices that say they support USB 2.0 Link PM
+ * when they're plugged into a USB 2.0 port, but they don't work when LPM is
+ * enabled.
+ *
+ * Only enable USB 2.0 Link PM if the port is internal (hardwired), or the
+ * device says it supports the new USB 2.0 Link PM errata by setting the BESL
+ * support bit in the BOS descriptor.
+ */
+static void hub_set_initial_usb2_lpm_policy(struct usb_device *udev)
+{
+       int connect_type;
+
+       if (!udev->usb2_hw_lpm_capable)
+               return;
+
+       connect_type = usb_get_hub_port_connect_type(udev->parent,
+                       udev->portnum);
+
+       if ((udev->bos->ext_cap->bmAttributes & USB_BESL_SUPPORT) ||
+                       connect_type == USB_PORT_CONNECT_TYPE_HARD_WIRED) {
+               udev->usb2_hw_lpm_allowed = 1;
+               usb_set_usb2_hardware_lpm(udev, 1);
+       }
+}
+
 /* Reset device, (re)assign address, get device descriptor.
  * Device connection must be stable, no more debouncing needed.
  * Returns device in USB_STATE_ADDRESS, except on error.
@@ -4246,6 +4272,7 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
        /* notify HCD that we have a device connected and addressed */
        if (hcd->driver->update_device)
                hcd->driver->update_device(hcd, udev);
+       hub_set_initial_usb2_lpm_policy(udev);
 fail:
        if (retval) {
                hub_port_disable(hub, port1, 0);