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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 64150C433B4 for ; Mon, 19 Apr 2021 14:19:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3D09461221 for ; Mon, 19 Apr 2021 14:19:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238998AbhDSOT6 (ORCPT ); Mon, 19 Apr 2021 10:19:58 -0400 Received: from netrider.rowland.org ([192.131.102.5]:52119 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S232452AbhDSOTz (ORCPT ); Mon, 19 Apr 2021 10:19:55 -0400 Received: (qmail 134732 invoked by uid 1000); 19 Apr 2021 10:19:21 -0400 Date: Mon, 19 Apr 2021 10:19:21 -0400 From: Alan Stern To: Chris Chiu Cc: Greg KH , m.v.b@runbox.com, hadess@hadess.net, linux-usb@vger.kernel.org, Linux Kernel Subject: Re: [PATCH v3] USB: Don't set USB_PORT_FEAT_SUSPEND on WD19's Realtek Hub Message-ID: <20210419141921.GA133494@rowland.harvard.edu> References: <20210415114856.4555-1-chris.chiu@canonical.com> <20210415184637.GA15445@rowland.harvard.edu> <20210416153932.GD42403@rowland.harvard.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 19, 2021 at 01:11:38AM -0400, Chris Chiu wrote: > Sorry that I didn't make myself clear. I found that if I applied RESET_RESUME > quirk on the problematic hub, the Set-Port-Feature(suspend) timeout error > disappeared. SInce the timeout is not happening for each suspend by default, > I suspect maybe reset-resume take everything back to clean state for the hub > and the Set-Port-Feature(suspend) can be taken care of w/o problems. Okay, that's a good solution for system suspend. > I didn't like RESET_RESUME because runtime PM would not work on the quirked > device. A more interesting question is whether it will work for devices plugged into the hub. Even though the hub won't be runtime suspended, the things attached to it might be. > But if the Set-Port-Feature(suspend) can't be handled and > skipped, I can't > expect the runtime PM to work for all devices connected to the hub either. > Is that right? If what I proposed in the patch can not get better > result than existing > quirk, I think using the RESET_RESUME would be a better option. Any suggestions? Try the RESET_RESUME quirk and see how well it works with runtime suspend. Alan Stern