From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757894AbcEFHDc (ORCPT ); Fri, 6 May 2016 03:03:32 -0400 Received: from mga03.intel.com ([134.134.136.65]:20503 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751420AbcEFHDa (ORCPT ); Fri, 6 May 2016 03:03:30 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,586,1455004800"; d="asc'?scan'208";a="960060519" From: Felipe Balbi To: Peter Chen 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 In-Reply-To: <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> <20160505080637.GA19426@shlinux2.ap.freescale.net> User-Agent: Notmuch/0.21+96~g9bbc54b (http://notmuchmail.org) Emacs/25.0.90.3 (x86_64-pc-linux-gnu) Date: Fri, 06 May 2016 10:01:20 +0300 Message-ID: <878tznisan.fsf@intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha1; protocol="application/pgp-signature" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Hi, Peter Chen writes: >> "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. >>=20 >> 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. >>=20 >> 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. >>=20 > > 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? this is the detail that I'm not yet entirely sure is always valid. Would there ever be a situation where we want to drop pull-ups but not tell the gadget about it ? I'm not sure. Anybody wants to investigate ? Otherwise I'll add it to my TODO list. =2D-=20 balbi --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJXLEFAAAoJEIaOsuA1yqREZgIQAJGyZGIGRhdtY+tKG59rud0f Ijp5qmT+OpMXTQdN7CVcclaSZ5ZGdzLl1Di2OYwvYOWjmZ4mB8oTOZha3tliWZ3d NEzDhZ8vP75Vds/FlniWRR5zNWEJq2kvs/2KgFYjgPK+4gTcdXMruukL8zMprlQA oM5yUPSy6qqHPAvta+301SxI2+MtazRQ3kcDvXlE+CNMd0UvS6cKwjvkLQOmmbim qybzlY0BK6MitT+qENjZDlBEJjplU9IN0MOdl4yhIurzRlKfz744XgIEFtQVnJhV /JS5eCeTHtIYUyAveP8twCEq7RK3MSMXLWMxjeCxzB79N/pk+4Hy/8aZP4JYsdXC Lq/2UrCoAZtL3AwoPoUGRP13h4d/ibxWYi9SdS0suwtxcvYSNmWnEAWzJhO1P3mK f451kW02b8ebaNHgVsMuvaKQGDmR69zWudTvTBFv3/X0me3URhxt9KacM8OC52oq EUvcRu0SA7ytWugT/nv20pUoaG+2nAYJk5//RfWd54QIJnIqJtDBfm/BqdsC4QHa 8rRqctiozZfoqgsTkxI2W/sAPtyfgE48RFZh9YShgl7duUk02c71ekDDUeEzGKcI 8EjqvN/c4DjlY/+keKY/yT7miqM4qf2I2Ldak6Z2+6HYRAGZPLQVaKgQKAL178FK EIgHSi10B+nTbeUkFVF1 =LCtJ -----END PGP SIGNATURE----- --=-=-=--