From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E450EC33CB1 for ; Wed, 15 Jan 2020 12:21:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B7E4D222C3 for ; Wed, 15 Jan 2020 12:21:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579090875; bh=f1oJB8fmMEk1uZlaxMqhY5MfMoD6s0r/AgRWoRE7bfw=; h=Subject:To:From:Date:List-ID:From; b=HefKkWyWoiTZ8+47y7yRsSsUJlRhvW+9w3eJG+RBlEjjXkNxrvIuu6MT05G26n2gh 58TiOk/riSDwZqHwDEl6JDDmSl9ntPIcj5BvG/JDjvp8YUVfuUN47qDcVRgB8SRHFe dzNV9ZQ7vqnUCLQbLAqiy03BVbTLlDxzZSldStj4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730401AbgAOMVP (ORCPT ); Wed, 15 Jan 2020 07:21:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:46490 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730333AbgAOMVP (ORCPT ); Wed, 15 Jan 2020 07:21:15 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7C001207FF; Wed, 15 Jan 2020 12:21:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579090874; bh=f1oJB8fmMEk1uZlaxMqhY5MfMoD6s0r/AgRWoRE7bfw=; h=Subject:To:From:Date:From; b=D0iOMgHsHQO3T5scDXRhXiaqF/YZ3XtSnOAEmOoFVfyeNA/eW5EaxeIea2/LiKCXT /62IjmS+UIRd9fprkT0dhzEOsRRC9hRXOFICfOk8S37AnBlXo2iYeT300pPXTJWfmp PThlw9sM+RwiRergiq9JopkZxAV/+l0Xf/iUnBTQ= Subject: patch "usb: core: hub: Improved device recognition on remote wakeup" added to usb-linus To: nobuta.keiya@fujitsu.com, gregkh@linuxfoundation.org, stable@vger.kernel.org, stern@rowland.harvard.edu From: Date: Wed, 15 Jan 2020 13:21:11 +0100 Message-ID: <157909087124168@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org This is a note to let you know that I've just added the patch titled usb: core: hub: Improved device recognition on remote wakeup 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 9c06ac4c83df6d6fbdbf7488fbad822b4002ba19 Mon Sep 17 00:00:00 2001 From: Keiya Nobuta Date: Thu, 9 Jan 2020 14:14:48 +0900 Subject: usb: core: hub: Improved device recognition on remote wakeup If hub_activate() is called before D+ has stabilized after remote wakeup, the following situation might occur: __ ___________________ / \ / D+ __/ \__/ Hub _______________________________ | ^ ^ ^ | | | | Host _____v__|___|___________|______ | | | | | | | \-- Interrupt Transfer (*3) | | \-- ClearPortFeature (*2) | \-- GetPortStatus (*1) \-- Host detects remote wakeup - D+ goes high, Host starts running by remote wakeup - D+ is not stable, goes low - Host requests GetPortStatus at (*1) and gets the following hub status: - Current Connect Status bit is 0 - Connect Status Change bit is 1 - D+ stabilizes, goes high - Host requests ClearPortFeature and thus Connect Status Change bit is cleared at (*2) - After waiting 100 ms, Host starts the Interrupt Transfer at (*3) - Since the Connect Status Change bit is 0, Hub returns NAK. In this case, port_event() is not called in hub_event() and Host cannot recognize device. To solve this issue, flag change_bits even if only Connect Status Change bit is 1 when got in the first GetPortStatus. This issue occurs rarely because it only if D+ changes during a very short time between GetPortStatus and ClearPortFeature. However, it is fatal if it occurs in embedded system. Signed-off-by: Keiya Nobuta Cc: stable Acked-by: Alan Stern Link: https://lore.kernel.org/r/20200109051448.28150-1-nobuta.keiya@fujitsu.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hub.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 8c4e5adbf820..3405b146edc9 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -1192,6 +1192,7 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type) * PORT_OVER_CURRENT is not. So check for any of them. */ if (udev || (portstatus & USB_PORT_STAT_CONNECTION) || + (portchange & USB_PORT_STAT_C_CONNECTION) || (portstatus & USB_PORT_STAT_OVERCURRENT) || (portchange & USB_PORT_STAT_C_OVERCURRENT)) set_bit(port1, hub->change_bits); -- 2.24.1