patch "usb: core: Fix hub port connection events lost" added to usb-linus

This is a note to let you know that I've just added the patch titled

usb: core: Fix hub port connection events lost

to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From: Dennis Wassenberg <[email protected]>
Date: Tue, 13 Nov 2018 14:40:34 +0100
Subject: usb: core: Fix hub port connection events lost

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.

---
 drivers/usb/core/hub.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

index d9bd7576786a..0f9381b69a3b 100644
@@ -2850,7 +2850,9 @@ 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);
 
 			/*

2.19.1