usb: core: Fix hub port connection events lost
authorDennis Wassenberg <dennis.wassenberg@secunet.com>
Tue, 13 Nov 2018 13:40:34 +0000 (14:40 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 1 Dec 2018 08:42:49 +0000 (09:42 +0100)
commit427d4e4c27442ed2329a9672f65af49cd5a56389
tree0c6a14a5b74b0808668def0ac6a1e1f23984702f
parent5d47e129a7107d6f35ac4ce7f32ff9376b555bfe
usb: core: Fix hub port connection events lost

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