From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756312AbcEEIO7 (ORCPT ); Thu, 5 May 2016 04:14:59 -0400 Received: from mail-pa0-f65.google.com ([209.85.220.65]:34028 "EHLO mail-pa0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755562AbcEEIOz (ORCPT ); Thu, 5 May 2016 04:14:55 -0400 Date: Thu, 5 May 2016 16:06:37 +0800 From: Peter Chen To: Felipe Balbi Cc: "Du, Changbin" , "gregkh@linuxfoundation.org" , "linux-usb@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] usb: dwc3: usb/dwc3: fake dissconnect event when turn off pullup Message-ID: <20160505080637.GA19426@shlinux2.ap.freescale.net> References: <1461745745-3954-1-git-send-email-changbin.du@intel.com> <87wpnjmm7u.fsf@intel.com> <0C18FE92A7765D4EB9EE5D38D86A563A05D1E1A7@SHSMSX103.ccr.corp.intel.com> <87vb32kz7s.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87vb32kz7s.fsf@intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 28, 2016 at 09:46:15AM +0300, Felipe Balbi wrote: > > Hi, > > (we don't top-post on this forum ;-) > > "Du, Changbin" writes: > > Hi, Balbi, > > > > The step to reproduce this issue is: > > 1) connect device to a host and wait its enumeration. > > 2) trigger software disconnect by calling function > > usb_gadget_disconnect(), which finally call > > dwc3_gadget_pullup(false). Do not reconnect device > > (I mean no enumeration go on, keep bit Run/Stop 0.). > > > > At here, gadget driver's disconnect callback should be > > Called, right? We has been disconnected. But no, as > > You said " not generating disconnect IRQ after you > > drop Run/Stop is expected". > > > > And I am testing on an Android device, Android only > > use dwc3_gadget_pullup(false) to issue a soft disconnection. > > This confused user that the UI still show usb as connected > > State, caused by missing a disconnect event. > > okay, so I know what this is. This is caused by Android gadget itself > not notifying the gadget that a disconnect has happened. Just look at > udc-core's soft_connect implementation for the sysfs interface, and > you'll see what I mean. > > This should be fixed at Android gadget itself. The only thing we could > do is introduce a new usb_gadget_soft_connect()/disconnect() to wrap the > logic so it's easier for Android gadget to use; but even that I'm a > little bit reluctant to do because Android should be using our > soft_connect interface instead of reimplementing it (wrongly) by its > own. > If it is a gadget driver, it can call its disconnect explicitly. Another thing is the gadget driver should not call usb_gadget_disconnect directly, it should call usb_gadget_deactivate or usb_function_deactivate. Since currently, calling usb_gadget_disconnect may not do real pull down dp, Felipe, will you consider adding gadget_driver->disconnect into usb_gadget_disconnect after pull down dp? -- Best Regards, Peter Chen