If the device isn't reset, the XHCI HCD sends SET ADDRESS to address 0 while the device is already in Addressed state, and the request is dropped on the floor as it is addressed to the default address. This sequence of events, which this patch fixes looks like this: usb_reset_and_verify_device() hub_port_init() hub_set_address() SET_ADDRESS to 0 with 1 usb_get_device_descriptor(udev, 8) usb_get_device_descriptor(udev, 18) descriptors_changed() --> goto re_enumerate: hub_port_logical_disconnect() kick_khubd() And then: hub_events() hub_port_connect_change() usb_disconnect() usb_disable_device() new device struct sets device state to Powered choose_address() hub_port_init() <-- no reset, but SET ADDRESS to 0 with 1, timeout! The solution is to always reset the device in hub_port_init() to put it in a known state. Signed-off-by: Luben Tuikov <ltuikov@xxxxxxxxx> --- drivers/usb/core/hub.c | 18 +++++++----------- 1 files changed, 7 insertions(+), 11 deletions(-) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 4310cc4..7e8c482 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -2681,17 +2681,13 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1, mutex_lock(&usb_address0_mutex); - if (!udev->config && oldspeed == USB_SPEED_SUPER) { - /* Don't reset USB 3.0 devices during an initial setup */ - usb_set_device_state(udev, USB_STATE_DEFAULT); - } else { - /* Reset the device; full speed may morph to high speed */ - /* FIXME a USB 2.0 device may morph into SuperSpeed on reset. */ - retval = hub_port_reset(hub, port1, udev, delay); - if (retval < 0) /* error or disconnect */ - goto fail; - /* success, speed is known */ - } + /* Reset the device; full speed may morph to high speed */ + /* FIXME a USB 2.0 device may morph into SuperSpeed on reset. */ + retval = hub_port_reset(hub, port1, udev, delay); + if (retval < 0) /* error or disconnect */ + goto fail; + /* success, speed is known */ + retval = -ENODEV; if (oldspeed != USB_SPEED_UNKNOWN && oldspeed != udev->speed) { -- 1.7.0.1 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html