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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 13154C64E7C for ; Wed, 2 Dec 2020 08:58:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AD6C9221E9 for ; Wed, 2 Dec 2020 08:58:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729013AbgLBI6s (ORCPT ); Wed, 2 Dec 2020 03:58:48 -0500 Received: from mga06.intel.com ([134.134.136.31]:60111 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728480AbgLBI6r (ORCPT ); Wed, 2 Dec 2020 03:58:47 -0500 IronPort-SDR: 0TZnOfxn6T5fpdnipNG1vfcKS+zIxvWfAvbhjO67LZcGRurHUxC3wxRQgrHX9SKgH01DtlHJSh TBaoyk/6eQMw== X-IronPort-AV: E=McAfee;i="6000,8403,9822"; a="234588687" X-IronPort-AV: E=Sophos;i="5.78,386,1599548400"; d="scan'208";a="234588687" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Dec 2020 00:57:05 -0800 IronPort-SDR: AFF0GSwbUqo1qU+TpI7/aKK6PQ9T/WaJdKUw4zH2xFjETa19MMgx7XeroXvilGMeFbHKteJwKy wabg0w12+9xg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.78,386,1599548400"; d="scan'208";a="345796824" Received: from mattu-haswell.fi.intel.com (HELO [10.237.72.170]) ([10.237.72.170]) by orsmga002.jf.intel.com with ESMTP; 02 Dec 2020 00:57:04 -0800 Subject: Re: [PATCH] usb: host: xhci: wait USB2 port enter suspend for bus suspend To: Jun Li , "mathias.nyman@intel.com" Cc: "gregkh@linuxfoundation.org" , "linux-usb@vger.kernel.org" , Peter Chen References: <1604402250-16434-1-git-send-email-jun.li@nxp.com> <9b8d9be1-a6e4-e861-1d91-a62a97ac3add@linux.intel.com> From: Mathias Nyman Autocrypt: addr=mathias.nyman@linux.intel.com; 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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On 2.12.2020 8.58, Jun Li wrote: > > >> -----Original Message----- >> From: Mathias Nyman >> Sent: Wednesday, December 2, 2020 7:55 AM >> To: Jun Li ; mathias.nyman@intel.com >> Cc: gregkh@linuxfoundation.org; linux-usb@vger.kernel.org; Peter Chen >> >> Subject: Re: [PATCH] usb: host: xhci: wait USB2 port enter suspend for bus >> suspend >> >> Hi >> >> On 1.12.2020 8.12, Jun Li wrote: >>> Hi, >>> >>>> -----Original Message----- >>>> From: Jun Li >>>> Sent: Tuesday, November 3, 2020 7:23 PM >>>> To: mathias.nyman@intel.com >>>> Cc: gregkh@linuxfoundation.org; linux-usb@vger.kernel.org; Peter Chen >>>> >>>> Subject: [PATCH] usb: host: xhci: wait USB2 port enter suspend for >>>> bus suspend >>>> >>>> If the connected USB2 device wakeup is not enabled/supported, the >>>> link state may still be U0 when do xhci bus suspend, after we suspend >>>> ports in U0, we need give time to device to enter suspend before do >>>> further suspend operations (e.g. system suspend), otherwise we may >>>> enter system suspend with link state at U0. >> >> >> What side-effects have you observed if bus suspend returns while a port is >> still transitioning to U3? > > I found a real problem on remote wakeup by USB2 device disconnect > on root port, that device(e.g. Udisk) itself does not support remote > wakeup, the remote wakeup has problem if I enable USB2 DPDM wakeup > when USB2 bus at U0. > >> >> I can't recall why we end up with ports in U0 in bus suspend anymore. >> I think that in system suspend the link should be put to U3 already when >> the usb device is suspended, before the bus suspends, even if it doesn't >> support remote wakeup. > > I also thought so but actually not, see below in usb_port_suspend(): > > 12 if (hub_is_superspeed(hub->hdev)) > 13 status = hub_set_port_link_state(hub, port1, USB_SS_PORT_LS_U3); > 14 > 15 /* > 16 * For system suspend, we do not need to enable the suspend feature > 17 * on individual USB-2 ports. The devices will automatically go > 18 * into suspend a few ms after the root hub stops sending packets. > 19 * The USB 2.0 spec calls this "global suspend". > 20 * > 21 * However, many USB hubs have a bug: They don't relay wakeup requests > 22 * from a downstream port if the port's suspend feature isn't on. > 23 * Therefore we will turn on the suspend feature if udev or any of its > 24 * descendants is enabled for remote wakeup. > 25 */ > 26 else if (PMSG_IS_AUTO(msg) || usb_wakeup_enabled_descendants(udev) > 0) > 27 status = set_port_feature(hub->hdev, port1, > 28 USB_PORT_FEAT_SUSPEND); > 29 else { > 30 really_suspend = false; > 31 status = 0; > 32 } > > usb_wakeup_enabled_descendants(udev) > 0 is not true, if the device itself > does not support remote wakeup. > You're right, link isn't set to U3 in this case. ... >> >> if (bus_state->bus_suspended) >> usleep_range(5000, 10000) > > I will send your proposal if no more comments. Yes, thanks, no more comments. -Mathias