usb: hub: Clear Port Reset Change during init/resume

This patch adds the Port Reset Change flag to the set of bits that are
preemptively cleared on init/resume of a hub. In theory this bit should
never be set unexpectedly... in practice it can still happen if BIOS,
SMM or ACPI code plays around with USB devices without cleaning up
correctly. This is especially dangerous for XHCI root hubs, which don't
generate any more Port Status Change Events until all change bits are
cleared, so this is a good precaution to have (similar to how it's
already done for the Warm Port Reset Change flag).

Signed-off-by: Julius Werner <jwerner@chromium.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 3f8933f10e7dc569c7235b1daa0a642a8cb3974e..92dde941fdbe48b7dd6f33b4f703f12fcf6d7a52 100644 (file)
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1135,6 +1135,11 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
                        usb_clear_port_feature(hub->hdev, port1,
                                        USB_PORT_FEAT_C_ENABLE);
                }
+               if (portchange & USB_PORT_STAT_C_RESET) {
+                       need_debounce_delay = true;
+                       usb_clear_port_feature(hub->hdev, port1,
+                                       USB_PORT_FEAT_C_RESET);
+               }
                if ((portchange & USB_PORT_STAT_C_BH_RESET) &&
                                hub_is_superspeed(hub->hdev)) {
                        need_debounce_delay = true;