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=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 E7DC8C0650F for ; Mon, 5 Aug 2019 13:26:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B39FD20651 for ; Mon, 5 Aug 2019 13:26:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565011583; bh=kz4IhatFXf46gUFuUUXsCZznBc6ohCoNL4N8twIq4lI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=jzB5hR/8Zb7IyYC43NdrDXrDotDHqC96lpjvvlRnJIW3QUOLGfx40ecJjkabzE3fo bRDbIzFembGPEPChnA+Lx/8TNMGf1vPSq4O3aMYdxm1udwxy36fXnYR51U+PFi305E j7tPPD8eN0r/AyxebMxP39uFOrw5Q0YbRskgBWpI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731447AbfHEN0X (ORCPT ); Mon, 5 Aug 2019 09:26:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:34878 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731395AbfHEN0Q (ORCPT ); Mon, 5 Aug 2019 09:26:16 -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 B9E8220651; Mon, 5 Aug 2019 13:26:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565011575; bh=kz4IhatFXf46gUFuUUXsCZznBc6ohCoNL4N8twIq4lI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jZFBe8/AkcnYLk4tfbGogE+A4zQ0BR0UMJUVmfqchUwAsDiE6efqFyuP3Ir8Qg1ig gmJQojfPE/+PfpNaalnSGUO40Eb6vNrXCRcf6Av4J8cybgTrLUDoEmp+dimzgnfdis DZc2AIoV0oFKPdKPMxAGGwdcthYKIp+dUcpU0jG4= Date: Mon, 5 Aug 2019 15:06:21 +0200 From: Greg KH To: Kai-Heng Feng Cc: Alan Stern , Mathias Nyman , Linux USB List , lkml Subject: Re: [PATCH v2] USB: Disable USB2 LPM at shutdown Message-ID: <20190805130621.GA25026@kroah.com> References: <46147522-7BC2-4C30-B3E5-6568E9642982@canonical.com> <27A5C1CC-E0A4-4CAF-B81E-90EE76C8A887@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <27A5C1CC-E0A4-4CAF-B81E-90EE76C8A887@canonical.com> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 05, 2019 at 08:58:33PM +0800, Kai-Heng Feng wrote: > Hi Greg, > > at 17:22, Kai-Heng Feng wrote: > > > at 22:17, Alan Stern wrote: > > > > > > I agree with Kai-Heng, this seems like a fairly light-weight solution > > > to a reasonable problem. > > > > Thanks for your review. > > > > > As to the issue of how much it will slow down system shutdowns, I have > > > no idea. Probably not very much, unless somebody has an unusually > > > large number of USB devices plugged in, but only testing can give a > > > real answer. > > > > In addition to that, only USB2 devices that enable LPM will slow down > > shutdown process. > > Right now only internally connected USB2 devices enable LPM, so the > > numbers are even lower. > > > > > I suppose we could add an HCD flag for host controllers which require > > > this workaround. Either way, it's probably not a very big deal. > > > > IMO this is not necessary. Only xHCI that reports hw_lpm_support will be > > affected. At least for PC, this only became true after Whiskey Lake. > > > > Kai-Heng > > > > > Alan Stern > > This patch is included in Ubuntu’s kernel for a while now, and there’s no > regression report so far. > Please consider merge this patch. I do not see a patch here at all, sorry. Please resend it. greg k-h