diff options
Diffstat (limited to 'drivers/usb/core/hub.c')
| -rw-r--r-- | drivers/usb/core/hub.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 9be1a2d5fba6..566ac5531407 100644 --- 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); |