Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933742AbaGQNef (ORCPT ); Thu, 17 Jul 2014 09:34:35 -0400 Received: from mail-pa0-f50.google.com ([209.85.220.50]:63471 "EHLO mail-pa0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932400AbaGQNeb (ORCPT ); Thu, 17 Jul 2014 09:34:31 -0400 From: Gavin Guo To: stern@rowland.harvard.edu, sarah.a.sharp@linux.intel.com, mathias.nyman@intel.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Cc: yk@canonical.com, anthony.wong@canonical.com, gerald.yang@canonical.com Subject: [PATCH v2 1/1] usb: Check if port status is equal to RxDetect Date: Thu, 17 Jul 2014 21:34:16 +0800 Message-Id: <1405604056-18987-2-git-send-email-gavin.guo@canonical.com> X-Mailer: git-send-email 2.0.0 In-Reply-To: <1405604056-18987-1-git-send-email-gavin.guo@canonical.com> References: <1405604056-18987-1-git-send-email-gavin.guo@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When using USB 3.0 pen drive with the [AMD] FCH USB XHCI Controller [1022:7814], the second hotplugging will experience the USB 3.0 pen drive is recognized as high-speed device. After bisecting the kernel, I found the commit number 41e7e056cdc662f704fa9262e5c6e213b4ab45dd (USB: Allow USB 3.0 ports to be disabled.) causes the bug. After doing some experiments, the bug can be fixed by avoiding executing the function hub_usb3_port_disable(). Because the port status with [AMD] FCH USB XHCI Controlleris [1022:7814] is already in RxDetect (I tried printing out the port status before setting to Disabled state), it's reasonable to check the port status before really executing hub_usb3_port_disable(). Fixes: 41e7e056cdc6 (USB: Allow USB 3.0 ports to be disabled.) Signed-off-by: Gavin Guo Signed-off-by: Alan Stern Cc: --- drivers/usb/core/hub.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 21b99b4..0e950ad 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -889,6 +889,25 @@ static int hub_usb3_port_disable(struct usb_hub *hub, int port1) if (!hub_is_superspeed(hub->hdev)) return -EINVAL; + ret = hub_port_status(hub, port1, &portstatus, &portchange); + if (ret < 0) + return ret; + + /* + * USB controller Advanced Micro Devices, Inc. [AMD] FCH USB XHCI + * Controller [1022:7814] will have spurious result making the following + * usb 3.0 device hotplugging route to the 2.0 root hub and recognized + * as high-speed device if we set the usb 3.0 port link state to + * Disabled. Since it's already in USB_SS_PORT_LS_RX_DETECT state, we + * check the state here to avoid the bug. + */ + if ((portstatus & USB_PORT_STAT_LINK_STATE) == + USB_SS_PORT_LS_RX_DETECT) { + dev_dbg(&hub->ports[port1 - 1]->dev, + "Not disabling port; link state is RxDetect\n"); + return ret; + } + ret = hub_set_port_link_state(hub, port1, USB_SS_PORT_LS_SS_DISABLED); if (ret) return ret; -- 2.0.0 -- 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/