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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 B2DE7C0650E for ; Fri, 5 Jul 2019 01:37:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8DBFD21852 for ; Fri, 5 Jul 2019 01:37:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727391AbfGEBhJ (ORCPT ); Thu, 4 Jul 2019 21:37:09 -0400 Received: from netrider.rowland.org ([192.131.102.5]:36635 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1727345AbfGEBhJ (ORCPT ); Thu, 4 Jul 2019 21:37:09 -0400 Received: (qmail 1221 invoked by uid 500); 4 Jul 2019 21:37:08 -0400 Received: from localhost (sendmail-bs@127.0.0.1) by localhost with SMTP; 4 Jul 2019 21:37:08 -0400 Date: Thu, 4 Jul 2019 21:37:08 -0400 (EDT) From: Alan Stern X-X-Sender: stern@netrider.rowland.org To: Benjamin Herrenschmidt cc: Felipe Balbi , "linux-usb@vger.kernel.org" , Michal Nazarewicz Subject: Re: Virtual hub, resets etc... In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Fri, 5 Jul 2019, Benjamin Herrenschmidt wrote: > On Fri, 2019-07-05 at 07:44 +1000, Benjamin Herrenschmidt wrote: > > > > - At some point I had code to reject EP queue() if the device > > > > is > > > > suspended with -ESHUTDOWN. The end result was bad ... > > > > f_mass_storage > > > > goes into an infinite loop of trying to queue the same stuff in > > > > start_out_transfer() when that happens. It looks like it's not > > > > really > > > > handling errors from queue() in a particularily useful way. > > > > > > Don't reject EP queue requests. Accept them as you would at any > > > time; > > > they will complete after the port is resumed. > > > > Except the suspend on a bus reset clears the port enable. You can't > > resume from that, only reset the port no ? Or am I missing something > > ? > > 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. Alan Stern