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.wassenb...@secunet.com>
---
drivers/usb/core/hub.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index c6077d582d29..2731fad6f659 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2849,7 +2849,9 @@ static int hub_port_reset(struct usb_hub *hub, int port1,
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);
/*
--
2.17.1
