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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 39BEDC433B4 for ; Fri, 7 May 2021 15:59:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EF48A61078 for ; Fri, 7 May 2021 15:59:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236310AbhEGQAJ (ORCPT ); Fri, 7 May 2021 12:00:09 -0400 Received: from netrider.rowland.org ([192.131.102.5]:59983 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S231130AbhEGQAI (ORCPT ); Fri, 7 May 2021 12:00:08 -0400 Received: (qmail 780607 invoked by uid 1000); 7 May 2021 11:59:08 -0400 Date: Fri, 7 May 2021 11:59:08 -0400 From: Alan Stern To: chris.chiu@canonical.com Cc: gregkh@linuxfoundation.org, m.v.b@runbox.com, hadess@hadess.net, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] USB: reset-resume the device when PORT_SUSPEND is set but timeout Message-ID: <20210507155908.GB776548@rowland.harvard.edu> References: <20210507093329.895-1-chris.chiu@canonical.com> <20210507093329.895-2-chris.chiu@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210507093329.895-2-chris.chiu@canonical.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 07, 2021 at 05:33:28PM +0800, chris.chiu@canonical.com wrote: > From: Chris Chiu > > On the Realtek hub of Dell Dock WD19, the port which has wakeup > enabled descendants will sometimes timeout when setting PORT_SUSPEND > feature. After checking the PORT_SUSPEND bit in wPortStatus, it is > already set. However, the hub will fail to activate because the > PORT_SUSPEND feature of that port is not cleared during resume. All > devices connecting via the port are lost after resume. > > This commit force reset-resume the device connected to the timeout > but suspended port so that the hub will have chance to clear the > PORT_SUSPEND feature during resume. > > Signed-off-by: Chris Chiu > --- > drivers/usb/core/hub.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c > index b2bc4b7c4289..18603949a8de 100644 > --- a/drivers/usb/core/hub.c > +++ b/drivers/usb/core/hub.c > @@ -3385,6 +3385,21 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg) > status = 0; > } > if (status) { > + if (status == -ETIMEDOUT) { > + u16 portstatus, portchange; > + > + status = hub_port_status(hub, port1, &portstatus, > + &portchange); Don't reuse status like this. There will be a problem if this line sets status to 0 but the port isn't actually suspended. Use a different variable instead. Alan Stern > + > + dev_dbg(&port_dev->dev, > + "suspend timeout, status %04x\n", portstatus); > + > + if (status == 0 && port_is_suspended(hub, portstatus)) { > + udev->reset_resume = 1; > + goto err_wakeup; > + } > + } > + > dev_dbg(&port_dev->dev, "can't suspend, status %d\n", status); > > /* Try to enable USB3 LTM again */ > -- > 2.20.1 >