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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 3D6E7C433E0 for ; Mon, 8 Jun 2020 07:05:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0AB37204EF for ; Mon, 8 Jun 2020 07:05:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591599930; bh=Cwb5EvcljlGuWZibUThhRbS8xMa0vQTQolaLMZ/c5as=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=Z2aUYsrBkPMnoK+lGpT8ZVBv9L47bqjfPNO6jD+rxQr0DYL/p+y46smv7kWac1SB/ TCHUOtiXgJOXnPX5RyptIn6hU30Vmf4CChteqdR/MwYZNgep0J33NZpz3qPyiGRYMz eRf4FNGFkEMkWUuRJJuYarrXOtNYm2g4t+AsBEV4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728993AbgFHHF3 (ORCPT ); Mon, 8 Jun 2020 03:05:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:59292 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728053AbgFHHF2 (ORCPT ); Mon, 8 Jun 2020 03:05:28 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 82AAC204EF; Mon, 8 Jun 2020 07:05:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591599927; bh=Cwb5EvcljlGuWZibUThhRbS8xMa0vQTQolaLMZ/c5as=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=O7C2gTuGrrDXWc++jYwOGas+TIDhSEWNm3KD/ejRL6r6ydrkpOQTJGVr/sjRYQCvO 0GBbVJ7ubizOlA6x2IGxvJDOyRw2XUdVaMvnUF/mdGxAf0ea8yutP1E1enV2XIS+0C Emmez8U3uopmEehE/09yMvgmv4CrqM+kMJY3zXbE= Date: Mon, 8 Jun 2020 09:05:24 +0200 From: Greg Kroah-Hartman To: Kai-Heng Feng Cc: mathias.nyman@intel.com, "open list:USB XHCI DRIVER" , open list Subject: Re: [PATCH 2/2] xhci: Poll for U0 after disabling USB2 LPM Message-ID: <20200608070524.GB247853@kroah.com> References: <20200520101811.2623-1-kai.heng.feng@canonical.com> <20200520101811.2623-2-kai.heng.feng@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 08, 2020 at 11:58:40AM +0800, Kai-Heng Feng wrote: > > > > On May 20, 2020, at 18:18, Kai-Heng Feng wrote: > > > > USB2 devices with LPM enabled may interrupt the system suspend: > > [ 932.510475] usb 1-7: usb suspend, wakeup 0 > > [ 932.510549] hub 1-0:1.0: hub_suspend > > [ 932.510581] usb usb1: bus suspend, wakeup 0 > > [ 932.510590] xhci_hcd 0000:00:14.0: port 9 not suspended > > [ 932.510593] xhci_hcd 0000:00:14.0: port 8 not suspended > > .. > > [ 932.520323] xhci_hcd 0000:00:14.0: Port change event, 1-7, id 7, portsc: 0x400e03 > > .. > > [ 932.591405] PM: pci_pm_suspend(): hcd_pci_suspend+0x0/0x30 returns -16 > > [ 932.591414] PM: dpm_run_callback(): pci_pm_suspend+0x0/0x160 returns -16 > > [ 932.591418] PM: Device 0000:00:14.0 failed to suspend async: error -16 > > > > During system suspend, USB core will let HC suspends the device if it > > doesn't have remote wakeup enabled and doesn't have any children. > > However, from the log above we can see that the usb 1-7 doesn't get bus > > suspended due to not in U0. After a while the port finished U2 -> U0 > > transition, interrupts the suspend process. > > > > The observation is that after disabling LPM, port doesn't transit to U0 > > immediately and can linger in U2. xHCI spec 4.23.5.2 states that the > > maximum exit latency for USB2 LPM should be BESL + 10us. The BESL for > > the affected device is advertised as 400us, which is still not enough > > based on my testing result. > > > > So let's use the maximum permitted latency, 10000, to poll for U0 > > status to solve the issue. > > > > Signed-off-by: Kai-Heng Feng > > A gentle ping... It is the middle of the merge window, we can't do anything with any new patch until after -rc1 is out. You know this... greg k-h