Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933117AbcCHKfl (ORCPT ); Tue, 8 Mar 2016 05:35:41 -0500 Received: from mga11.intel.com ([192.55.52.93]:23037 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753679AbcCHKfA (ORCPT ); Tue, 8 Mar 2016 05:35:00 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.22,556,1449561600"; d="asc'?scan'208";a="932063781" From: Felipe Balbi To: Krzysztof Opasiak , Felipe Ferreri Tonello , linux-usb@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Michal Nazarewicz , Clemens Ladisch Subject: Re: [PATCH 3/5] usb: gadget: gmidi: remove bus powered requirement on bmAttributes In-Reply-To: <56DEA61F.1060100@samsung.com> References: <1456947640-20673-1-git-send-email-eu@felipetonello.com> <1456947640-20673-4-git-send-email-eu@felipetonello.com> <87wppi67c5.fsf@ti.com> <270D9ECD-1810-48BC-BBE9-9C9DD5E44D4F@felipetonello.com> <87egbmkah0.fsf@intel.com> <56DD4C84.1090506@felipetonello.com> <87ziuaimf8.fsf@intel.com> <56DD6241.2000308@felipetonello.com> <87h9ghife2.fsf@intel.com> <56DEA61F.1060100@samsung.com> User-Agent: Notmuch/0.21 (http://notmuchmail.org) Emacs/25.0.90.3 (x86_64-pc-linux-gnu) Date: Tue, 08 Mar 2016 12:34:10 +0200 Message-ID: <8760wxi7h9.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-Length: 3014 Lines: 83 --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Hi, Krzysztof Opasiak writes: > [ text/plain ] > > > On 03/08/2016 08:43 AM, Felipe Balbi wrote: > (...) > >>>>> This is necessary because this driver is actually wrong in which is >>>>> asking for the host to power itself. This is not specified on USB-MIDI >>>>> specification, neither makes any sense since this configuration is >>>>> device specific. >>>>> >>>>> What is your suggestion to make it configurable? Maybe at compile-tim= e? >>>>> I really don't know what is the best solution if this is not something >>>>> you like it. >>>> >>>> well, you could use our configfs-based gadget interface. You don't >>>> really need to use gmidi.ko at all. In fact, we wanna do away with any >>>> static modules and rely only on configfs. If configfs doesn't let you >>>> change what you want/need, then we can talk about adding support for >>>> those. >>>> >>>> bMaxPower and bmAttributes sound like good things to have configurable >>>> over configfs but beware of what the USB specification says about them, >>>> we cannot let users violate the spec by passing bogus values on these >>>> fields. >>> >>> I agree that we should move to configfs, but the truth is that these >>> legacy devices are still useful. They just do one thing, mostly, but >>=20 >> yes, they are useful as they are. They don't need to be changed to be >> useful. Plus, you can have a gadget built with configfs that does only >> one thing. And you can do that with a simple shell script. >>=20 >>> its easy and simple to setup and use. So I think before we have some >>=20 >> so is configfs. >>=20 >>> sort of preset library of configfs-based gadget drivers, we still need >>> these modules. >>=20 >> there is already a library called libusbg. > > As libusbg itself is a little bit dead there is a fork called > libusbgx[1] and it is still active;) > > It already has support for f_midi so it is ready to use. heh, seems like usb libraries tend to get forked with an 'x' appended to their name. But thanks for the note. =2D-=20 balbi --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJW3qqiAAoJEIaOsuA1yqREQa4QAJfaOSvaZh9PpgxjPQDEajGC sF1kS7Ah2xyE5nS0HL9Ao7+o+Zi+OkpW7RgA0UU+fM2P/I9Hom/oon82ckDqsQQq OS9Jnlw9YR5Yudy7bBumBODAuH7NThglu1L5B0WSksivFhL2hxvB5Kbmqt9T9BNo ra+DNR1+SGY67bYHAHytdFDWakyM79KDrMKSaLY7zwP7Ea1zpB1qc1PJz7020NJ+ rfnWAs+hr3twydRWOSDD4x9UePhf6wKn2cJDvHQhxkP+WWBOyaIr1GIJJjqcHPXK jIAiNVZTN5SiWisXGTAbinv6UFJ2i0uNUd8/wI3FvBbXz9nEj2WSAUwx3xB3Sr+q hF519j9euk8C7nwn1uyny5JO0GV2HyuB6a6VSLwb/v45pq5uFWBWEspfRYr+eV4Z nQ1Q+ESA2sde0skWBYCE0iFnIvUE7f7i2OeXyRkkDHsKlsFV398xQFG4GKr57RQN R+fM6AQZS2FP2et5RrKkOCl/9NiKB+CaJOI/ZVlxqQBnMeeDt2v/Qo1CJLd/uzEw jE6eiZaDTPM7hmo6gVZJxAuRIdBrXpl7JnKrkiLoL2NuS49anU8C2Lj8EGAuScQN 6yP1H6cS9/zAVhGESo/4AE5GAoVMgW9bKs6OTYLkLqY6cpfiiYGfBKLcrTI9eViK 37fNOoyTx4cRzBUfG+/9 =n8sJ -----END PGP SIGNATURE----- --=-=-=--