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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 92FD2C0650E for ; Fri, 5 Jul 2019 02:15:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7054A20B1F for ; Fri, 5 Jul 2019 02:15:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727053AbfGECPx (ORCPT ); Thu, 4 Jul 2019 22:15:53 -0400 Received: from gate.crashing.org ([63.228.1.57]:40041 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726404AbfGECPx (ORCPT ); Thu, 4 Jul 2019 22:15:53 -0400 Received: from localhost (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id x652FivE005015; Thu, 4 Jul 2019 21:15:45 -0500 Message-ID: Subject: Re: Virtual hub, resets etc... From: Benjamin Herrenschmidt To: Alan Stern Cc: Felipe Balbi , "linux-usb@vger.kernel.org" , Michal Nazarewicz Date: Fri, 05 Jul 2019 12:15:44 +1000 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Thu, 2019-07-04 at 21:37 -0400, Alan Stern wrote: > > > > Talking of which... do we need this ? > > > > --- a/drivers/usb/gadget/composite.c > > +++ b/drivers/usb/gadget/composite.c > > @@ -1976,6 +1976,7 @@ void composite_disconnect(struct usb_gadget *gadget) > > * disconnect callbacks? > > */ > > spin_lock_irqsave(&cdev->lock, flags); > > + cdev->suspended = 0; > > if (cdev->config) > > reset_config(cdev); > > if (cdev->driver->disconnect) > > > > Otherwise with my vhub or with dummy_hcd, a suspend followed by a reset > > will keep that stale suspended flag to 1 (which has no effect at the moment > > but still...) > > > > If yes, I'll submit a patch accordingly... > > According to the USB spec, a host is not supposed to reset a suspended > port (it's supposed to resume the port and then do the reset). But of > course this can happen anyway, so we should handle it properly. Right. I do see the resume coming in, but I don't forward it to the gadget because here's what happens in that order: 1- Host gets shutdown (or cable disconnected) 2- Upstream bus suspend: I call ->suspend on the gadgets on all enabled ports that don't have USB_PORT_STAT_SUSPEND already set. I don't change the port status, I don't set USB_PORT_STAT_SUSPEND 3- Machine gets turned back on (or cable reconnected) 4- Upstream bus resume: I call ->resume on the gadgets on all enabled ports that don't have USB_PORT_STAT_SUSPEND set. 5- Upstream bus reset: I call ->suspend on all enabled ports after clearing their status (I preserve only USB_PORT_STAT_SUSPEND and USB_PORT_STAT_POWER which is always set for me). Note: I currently do this even if the port had USB_PORT_STAT_SUSPEND set, so such as port will get a double suspend ... maybe I shouldn't. 6- Hosts sets port reset: I reset the gadget since it's already bound/enabled. It's still "suspended". So we do have a legitimate case of "reset while suspended". I'll tidy up the patch and submit it. Cheers, Ben.