From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752791AbcEMMsi (ORCPT ); Fri, 13 May 2016 08:48:38 -0400 Received: from mga09.intel.com ([134.134.136.24]:47206 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751900AbcEMMsh (ORCPT ); Fri, 13 May 2016 08:48:37 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,614,1455004800"; d="asc'?scan'208";a="965839738" From: Felipe Balbi To: Baolin Wang Cc: Greg KH , Mark Brown , USB , LKML Subject: Re: [PATCH] dwc3: gadget: Defer starting the gadget device until gadget is power on In-Reply-To: References: <4d6528e4b742cacf34f384b766a7c3296dfe9dbf.1463134786.git.baolin.wang@linaro.org> <87oa8aqlzh.fsf@linux.intel.com> <87d1oqqhvs.fsf@linux.intel.com> User-Agent: Notmuch/0.22+11~g124a67e (http://notmuchmail.org) Emacs/25.0.93.2 (x86_64-pc-linux-gnu) Date: Fri, 13 May 2016 15:46:24 +0300 Message-ID: <871t56qg67.fsf@linux.intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; 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, Baolin Wang writes: >>>> why does it need restart? Why is dwc3 powered off? Who powers it off? >>> >>> Because when the dwc3 Vbus is off (no cable pluging in now), >>> especially for some mobile device, the system need to power off the >>> dwc3 to save power in this situation. >> >> but dwc3 doesn't do this by itself, so who's doing it? > > Yes, the dwc3 clock is controlled by the Soc system, so the Soc system > can disable the dwc3 clock when there is no cable plugging in. understood. >>>> This looks like a *really* bad power management implementation. Do you >>>> have hibernation enabled? Do you have Clock gating enabled? Which dwc3 >>>> version are you using? How was it configured? >>> >>> This is not hibernation, we want to power off the dwc3 to save power >>> when no cable plugging in. Yes, we have clock gating, at this >>> situation we will disable the clock and shutdown the phy to save >>> power. For mobile device, most time no cable plugging in, so we need >>> to think about the power consuming. How do you think this requirement? >> >> Well, seems like you're missing *proper* runtime PM. I've been meaning >> to work on it for weeks, but I still have a few other things to do >> before I get to that. In any case, we don't need to do what you did >> here. There are better ways. > > Make sense. cool, if you wanna work on it, let me know and I can give some details of what I have in mind. =2D-=20 balbi --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJXNcygAAoJEIaOsuA1yqREtfMQAI2D1IeX1gfJn3B/7WoAsfQb ySqx932pDgFAgGBuWjV3FLFC8ELXUizbJshXhzxvzuuEI4brzD+0YbHQVKXL9sPo gwXVVdd5DUTLWiWXBvEpk7HEOm5QMAHr5OFZMn3Vm7KptDJYRNlHLTTYupQB0nY1 1hpLjbZBKdq+mgrTgYXG1xq52+VK0el0tAQ9OLTek7JBdQJDvQWB8UvQMGmqy32l U/lBYcqhZLjPu2Vuy16AhDa95SVRVCf3cCkJhLRtD+SvuZ30SvAZMvkTI51J+k9t 8hq4m5JS51RS4Uv44YYtWaiu3BVN4q8sIc3F3XEcnQMvmQsdxUbKcCeFjpdtQ7cO W673lznUXISWqVu/OLFuNstHtR/T5yvkrTjU+Rur8Wyy+Bi2XYOvYo+Q8at3EIBX 4QMspK59A1R3bZNTIPktgt65KrGyFvVAnTDcxJ1cOLsfEzMxid8lhyWGgiD445pW jK7dtAEbAqJi9PCR5X8D6Kojf0ZArpCsY+eVTZc+y3NJZ61aS79MoHItExqyhUq7 FeGuxTv4xOasUV1x843ayv/4V+gT2cQJzGKJZUT+BSXEQ0GlaNoPbThaX0jJMQ01 kwAjPeP78zcBv8yZUdCqOKLc29Poo5Kmhyf6178vtZrQFRNWbcUQS9zcesfznsPi 8wOS96dvoKNPGjK1lv+h =Dy92 -----END PGP SIGNATURE----- --=-=-=--