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=-15.3 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 0E0BCC433B4 for ; Thu, 13 May 2021 14:35:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E115261354 for ; Thu, 13 May 2021 14:35:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234539AbhEMOg7 (ORCPT ); Thu, 13 May 2021 10:36:59 -0400 Received: from netrider.rowland.org ([192.131.102.5]:51319 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S234496AbhEMOgk (ORCPT ); Thu, 13 May 2021 10:36:40 -0400 Received: (qmail 968704 invoked by uid 1000); 13 May 2021 10:35:29 -0400 Date: Thu, 13 May 2021 10:35:29 -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 v3 1/2] USB: Verify the port status when timeout happens during port suspend Message-ID: <20210513143529.GD967812@rowland.harvard.edu> References: <20210513041446.3082-1-chris.chiu@canonical.com> <20210513041446.3082-2-chris.chiu@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210513041446.3082-2-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 Thu, May 13, 2021 at 12:14:45PM +0800, chris.chiu@canonical.com wrote: > From: Chris Chiu > > On the Realtek high-speed Hub(0bda:5487), 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 > connected devices are lost after resume. The last two sentences of this paragraph are now inaccurate. Please fix them up to match the current patch version. > Check the port status to verify whether it's really suspended when > timeout happpens. If yes, mark it as suspended so the device can > be resumed correctly. > > Signed-off-by: Chris Chiu > --- > > Changelog: > v3: > - create a new goto target for the timeout case instead of > reset_resume > - Revise the commit title/message because reset_resume is not > required. > v2: > - create a new variable to keep the result of hub_port_status > when suspend timeout. > > 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 b2bc4b7c4289..c5d64175eaa9 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; > + Extra blank line. > + int ret = hub_port_status(hub, port1, &portstatus, > + &portchange); > + > + dev_dbg(&port_dev->dev, > + "suspend timeout, status %04x\n", portstatus); The portstatus value shouldn't be printed if ret < 0, because it won't be initialized. If you want, initialize portstatus to 0 in the declaration. Also, there should be a comment here explaining why this code is needed. It should say pretty the same thing as the patch description, but more briefly (two sentences should be sufficient). Alan Stern > + > + if (ret == 0 && port_is_suspended(hub, portstatus)) { > + status = 0; > + goto suspend_done; > + } > + } > + > dev_dbg(&port_dev->dev, "can't suspend, status %d\n", status); > > /* Try to enable USB3 LTM again */ > @@ -3401,6 +3416,7 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg) > if (!PMSG_IS_AUTO(msg)) > status = 0; > } else { > + suspend_done: > dev_dbg(&udev->dev, "usb %ssuspend, wakeup %d\n", > (PMSG_IS_AUTO(msg) ? "auto-" : ""), > udev->do_remote_wakeup); > -- > 2.20.1 >