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=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=unavailable 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 85A96C43603 for ; Wed, 11 Dec 2019 16:13:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 65D78208C3 for ; Wed, 11 Dec 2019 16:13:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731165AbfLKQNJ (ORCPT ); Wed, 11 Dec 2019 11:13:09 -0500 Received: from iolanthe.rowland.org ([192.131.102.54]:55056 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1730381AbfLKPI2 (ORCPT ); Wed, 11 Dec 2019 10:08:28 -0500 Received: (qmail 1705 invoked by uid 2102); 11 Dec 2019 10:08:27 -0500 Received: from localhost (sendmail-bs@127.0.0.1) by localhost with SMTP; 11 Dec 2019 10:08:27 -0500 Date: Wed, 11 Dec 2019 10:08:27 -0500 (EST) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Kai-Heng Feng , Mathias Nyman cc: Greg KH , USB list , Kernel development list Subject: Re: [PATCH v2 2/2] USB: core: Attempt power cycle port when it's in eSS.Disabled state In-Reply-To: <62C4527A-5231-4A69-BE7C-9844E2123A90@canonical.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 11 Dec 2019, Kai-Heng Feng wrote: > > > > On Nov 30, 2019, at 01:41, Kai-Heng Feng wrote: > > > > On Dell TB16, Realtek USB ethernet (r8152) connects to an SMSC hub which > > then connects to ASMedia xHCI's root hub: > > > > /: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 5000M > > |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/7p, 5000M > > |__ Port 2: Dev 3, If 0, Class=Vendor Specific Class, Driver=r8152, 5000M > > > > Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub > > Bus 004 Device 002: ID 0424:5537 Standard Microsystems Corp. USB5537B > > Bus 004 Device 003: ID 0bda:8153 Realtek Semiconductor Corp. RTL8153 Gigabit Ethernet Adapter > > > > The SMSC hub may disconnect after system resume from suspend. When this > > happens, the reset resume attempt fails, and the last resort to disable > > the port and see something comes up later, also fails. > > > > When the issue occurs, the link state stays in eSS.Disabled state > > despite the warm reset attempts. Accoding to spec this can be caused by > > invalid VBus, after some expiremets, the SMSC hub can be brought back > > after a powercycle. > > > > So let's power cycle the port at the end of reset resume attempt, if > > it's in eSS.Disabled state. > > If there's no objection, can this fix be reviewed and merged? > > Kai-Heng The patch is okay as far as I'm concerned, since it doesn't do anything for non-SuperSpeed connections. It should be reviewed by Mathias. Alan Stern > > > > Signed-off-by: Kai-Heng Feng > > --- > > v2: > > - Lower dev_info() to dev_dbg(). > > > > drivers/usb/core/hub.c | 16 ++++++++++++++++ > > 1 file changed, 16 insertions(+) > > > > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c > > index 6b6cd76ac5e6..a2e6001046f5 100644 > > --- a/drivers/usb/core/hub.c > > +++ b/drivers/usb/core/hub.c > > @@ -2739,6 +2739,18 @@ static bool hub_port_warm_reset_required(struct usb_hub *hub, int port1, > > || link_state == USB_SS_PORT_LS_COMP_MOD; > > } > > > > +static bool hub_port_power_cycle_required(struct usb_hub *hub, int port1, > > + u16 portstatus) > > +{ > > + u16 link_state; > > + > > + if (!hub_is_superspeed(hub->hdev)) > > + return false; > > + > > + link_state = portstatus & USB_PORT_STAT_LINK_STATE; > > + return link_state == USB_SS_PORT_LS_SS_DISABLED; > > +} > > + > > static void hub_port_power_cycle(struct usb_hub *hub, int port1) > > { > > struct usb_port *port_dev = hub->ports[port1 - 1]; > > @@ -3601,6 +3613,10 @@ int usb_port_resume(struct usb_device *udev, pm_message_t msg) > > if (status < 0) { > > dev_dbg(&udev->dev, "can't resume, status %d\n", status); > > hub_port_logical_disconnect(hub, port1); > > + if (hub_port_power_cycle_required(hub, port1, portstatus)) { > > + dev_dbg(&udev->dev, "device in disabled state, attempt power cycle\n"); > > + hub_port_power_cycle(hub, port1); > > + } > > } else { > > /* Try to enable USB2 hardware LPM */ > > usb_enable_usb2_hardware_lpm(udev); > > -- > > 2.17.1