4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dennis Wassenberg dennis.wassenberg@secunet.com
commit 22454b79e6de05fa61a2a72d00d2eed798abbb75 upstream.
This will clear the USB_PORT_FEAT_C_CONNECTION bit in case of a hub port reset only if a device is was attached to the hub port before resetting the hub port.
Using a Lenovo T480s attached to the ultra dock it was not possible to detect some usb-c devices at the dock usb-c ports because the hub_port_reset code will clear the USB_PORT_FEAT_C_CONNECTION bit after the actual hub port reset. Using this device combo the USB_PORT_FEAT_C_CONNECTION bit was set between the actual hub port reset and the clear of the USB_PORT_FEAT_C_CONNECTION bit. This ends up with clearing the USB_PORT_FEAT_C_CONNECTION bit after the new device was attached such that it was not detected.
This patch will not clear the USB_PORT_FEAT_C_CONNECTION bit if there is currently no device attached to the port before the hub port reset. This will avoid clearing the connection bit for new attached devices.
Signed-off-by: Dennis Wassenberg dennis.wassenberg@secunet.com Acked-by: Mathias Nyman mathias.nyman@linux.intel.com Cc: stable stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/usb/core/hub.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -2757,7 +2757,9 @@ static int hub_port_reset(struct usb_hub USB_PORT_FEAT_C_BH_PORT_RESET); usb_clear_port_feature(hub->hdev, port1, USB_PORT_FEAT_C_PORT_LINK_STATE); - usb_clear_port_feature(hub->hdev, port1, + + if (udev) + usb_clear_port_feature(hub->hdev, port1, USB_PORT_FEAT_C_CONNECTION);
/*