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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E9454C433EF for ; Fri, 26 Nov 2021 06:55:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235061AbhKZG60 (ORCPT ); Fri, 26 Nov 2021 01:58:26 -0500 Received: from mail.kernel.org ([198.145.29.99]:44120 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234932AbhKZG4X (ORCPT ); Fri, 26 Nov 2021 01:56:23 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 49F7F61107; Fri, 26 Nov 2021 06:53:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1637909591; bh=EkC+31WwzI8sHldf/U1UH0zdUBbQivdaXpJbEwDm3jk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=DRNvCji7VX4ICqh8fVlaGz0yve30ZkW+t/7xkxq9fSZPSyFEdhn9TndWClivJ4Ecu lotakZi50YuctBEwvbVJkut24vbxVloW6OXxjzd5NUHYmvkERu4xQ+ABZ5woCiIpwv vtkrNb6xR47zn1o1+VNKefaWJNnPOh0/uoifgWWs= Date: Fri, 26 Nov 2021 07:53:06 +0100 From: Greg KH To: Kai-Heng Feng Cc: stern@rowland.harvard.edu, mathias.nyman@linux.intel.com, Thinh Nguyen , Bixuan Cui , Andrew Lunn , Chris Chiu , Rajat Jain , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] usb: core: Avoid doing warm reset on disconnect event Message-ID: References: <20211126032622.1101448-1-kai.heng.feng@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20211126032622.1101448-1-kai.heng.feng@canonical.com> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Fri, Nov 26, 2021 at 11:26:21AM +0800, Kai-Heng Feng wrote: > Unplugging USB device may cause an incorrect warm reset loop: > [ 143.039019] xhci_hcd 0000:00:14.0: Port change event, 2-3, id 19, portsc: 0x4202c0 > [ 143.039025] xhci_hcd 0000:00:14.0: handle_port_status: starting usb2 port polling. > [ 143.039051] hub 2-0:1.0: state 7 ports 10 chg 0000 evt 0008 > [ 143.039058] xhci_hcd 0000:00:14.0: Get port status 2-3 read: 0x4202c0, return 0x4102c0 > [ 143.039092] xhci_hcd 0000:00:14.0: clear port3 connect change, portsc: 0x4002c0 > [ 143.039096] usb usb2-port3: link state change > [ 143.039099] xhci_hcd 0000:00:14.0: clear port3 link state change, portsc: 0x2c0 > [ 143.039101] usb usb2-port3: do warm reset > [ 143.096736] xhci_hcd 0000:00:14.0: Get port status 2-3 read: 0x2b0, return 0x2b0 > [ 143.096751] usb usb2-port3: not warm reset yet, waiting 50ms > [ 143.131500] xhci_hcd 0000:00:14.0: Can't queue urb, port error, link inactive > [ 143.138260] xhci_hcd 0000:00:14.0: Port change event, 2-3, id 19, portsc: 0x2802a0 > [ 143.138263] xhci_hcd 0000:00:14.0: handle_port_status: starting usb2 port polling. > [ 143.160756] xhci_hcd 0000:00:14.0: Get port status 2-3 read: 0x2802a0, return 0x3002a0 > [ 143.160798] usb usb2-port3: not warm reset yet, waiting 200ms > > The warm reset is due to its PLS is in eSS.Inactive state. However, USB > 3.2 spec table 10-13 mentions "Ports can be disabled by either a fault > condition (disconnect event or other fault condition)", xHCI 1.2 spec > table 5-27 also states that "This flag shall automatically be cleared to > ‘0’ by a disconnect event or other fault condition." on PED. > > So use CSC = 0 and PED = 0 as indication that device is disconnecting to > avoid doing warm reset. > > Signed-off-by: Kai-Heng Feng > --- > drivers/usb/core/hub.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c > index 86658a81d2844..abd5a83d194b0 100644 > --- a/drivers/usb/core/hub.c > +++ b/drivers/usb/core/hub.c > @@ -5530,6 +5530,7 @@ static void port_event(struct usb_hub *hub, int port1) > __must_hold(&port_dev->status_lock) > { > int connect_change; > + int disconnect = 0; bool? > struct usb_port *port_dev = hub->ports[port1 - 1]; > struct usb_device *udev = port_dev->child; > struct usb_device *hdev = hub->hdev; > @@ -5545,6 +5546,9 @@ static void port_event(struct usb_hub *hub, int port1) > if (portchange & USB_PORT_STAT_C_CONNECTION) { > usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_CONNECTION); > connect_change = 1; > + if (!(portstatus & USB_PORT_STAT_CONNECTION) && > + !(portstatus & USB_PORT_STAT_ENABLE)) > + disconnect = 1; > } > > if (portchange & USB_PORT_STAT_C_ENABLE) { > @@ -5613,7 +5617,7 @@ static void port_event(struct usb_hub *hub, int port1) > * Warm reset a USB3 protocol port if it's in > * SS.Inactive state. > */ > - if (hub_port_warm_reset_required(hub, port1, portstatus)) { > + if (hub_port_warm_reset_required(hub, port1, portstatus) && !disconnect) { Why is this problem just showing up now? What commit caused this regression? thanks, greg k-h