Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760020Ab3JPApJ (ORCPT ); Tue, 15 Oct 2013 20:45:09 -0400 Received: from mail-pd0-f170.google.com ([209.85.192.170]:64526 "EHLO mail-pd0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759851Ab3JPApH (ORCPT ); Tue, 15 Oct 2013 20:45:07 -0400 From: Julius Werner To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, Alan Stern , Sarah Sharp , Benson Leung , Vincent Palatin , Duncan Laurie , Julius Werner Subject: [PATCH v2] usb: hub: Clear Port Reset Change during init/resume Date: Tue, 15 Oct 2013 17:45:00 -0700 Message-Id: <1381884300-403-1-git-send-email-jwerner@chromium.org> X-Mailer: git-send-email 1.8.4 In-Reply-To: References: <1381872227-24757-1-git-send-email-jwerner@chromium.org> <525DB456.1040006@cogentembedded.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1530 Lines: 38 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 --- drivers/usb/core/hub.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index e6b682c..c3dd64c 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -1130,6 +1130,11 @@ 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; -- 1.7.12.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/