From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932341AbaEJBU0 (ORCPT ); Fri, 9 May 2014 21:20:26 -0400 Received: from top.free-electrons.com ([176.31.233.9]:49197 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757898AbaEJBUV (ORCPT ); Fri, 9 May 2014 21:20:21 -0400 Date: Fri, 9 May 2014 20:17:47 -0500 From: Maxime Ripard To: Alan Stern Cc: Hans de Goede , Emilio Lopez , Mike Turquette , kishon@ti.com, Boris Brezillon , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-usb@vger.kernel.org, kevin.z.m.zh@gmail.com, sunny@allwinnertech.com, shuge@allwinnertech.com, zhuzhenhua@allwinnertech.com, linux-sunxi@googlegroups.com, Boris BREZILLON Subject: Re: [PATCH 4/7] usb: ehci-platform: add optional reset controller retrieval Message-ID: <20140510011747.GI7047@lukather> References: <536B324C.1040806@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="1vEdgMWljt97yA53" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --1vEdgMWljt97yA53 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, May 08, 2014 at 10:07:25AM -0400, Alan Stern wrote: > On Thu, 8 May 2014, Hans de Goede wrote: >=20 > > Hi, > >=20 > > On 05/08/2014 12:00 AM, Maxime Ripard wrote: > > > On Wed, May 07, 2014 at 10:25:55AM -0400, Alan Stern wrote: > > >> On Tue, 6 May 2014, Maxime Ripard wrote: > > >> > > >>> From: Boris BREZILLON > > >>> > > >>> On the Allwinner's A31 SoC the reset line connected to the EHCI IP = has to > > >>> be deasserted for the EHCI block to be usable. > > >>> > > >>> Add support for an optional reset controller that will be deasserte= d on > > >>> power off and asserted on power on. > > >>> > > >>> Signed-off-by: Boris BREZILLON > > >>> Signed-off-by: Maxime Ripard > > >> > > >> Is this really a _reset_ line? That is, when you assert the reset= =20 > > >> line, does it actually reset the EHCI controller, or does it merely= =20 > > >> leave the controller in a partially powered-down state? > > >=20 > > > It actually resets the whole controller. > > >=20 > > >> The difference is important. During suspend, the controller is > > >> supposed to remember the state of the port connections as well as ot= her > > >> settings. If it doesn't, the controller and all attached USB devices > > >> will have to be reinitialized every time the controller resumes, whi= ch > > >> will increase the latency. > > >=20 > > > So you're saying that we should move this to the probe then? > >=20 > > Yes. >=20 > That's right. The controller should not be reset during suspend, if > you can possibly avoid it. >=20 > There isn't any real benefit to asserting the reset signal during=20 > suspend, is there? I mean, it won't use any less power, right? I don't think it will. I'll update the patches and send a new version. Thanks! Maxime --=20 Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com --1vEdgMWljt97yA53 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.14 (GNU/Linux) iQIcBAEBAgAGBQJTbX47AAoJEBx+YmzsjxAgWF8QAJz6cZUOZWU1ZzGSk6UozGO5 uB7NGuV4qC9/haKxU43j71nMLVhulumnAxZLCx9UkY6h/QjWA1PvDdcavVazm0iX m4Qm2LIFmMylUJdXvVdtEpFNs7Sw4SUHJS0rUGj5i0o6qmvILOJn0ltPbDpMZh+n WyivNp7BOhMZR+sn2hqOgIX/Is/hTEQpdZKHFhLhQTFOhynit+mLi/KhUGb1vYyD 2NrIt1QcU/HmHsSC83cOfUeAO22ar8pLmOwXET+s5BVINIJpL1IOzUS9CejIqSs+ HLRqIEwumqPKGqBn9IbGyL/nDg3k+hk0HMABCH7NA58ShAZUxWmi8Z3WwCAXzb0B 128oU37K0r/9LzOBlQADjP9jJSqMqO78Waz3HvaMaOZQAb3E8GSIP9AjKt5KMY/R RcLVqyq8Ojosf+ahYDuC5z9uUgqGcFoWE++8vCFT4plFUYXI9r6Hm5pzvZ0zBNt6 9voAYBI3BumvTsoybVY8ycTkwYIJAFIowd2kVlu49GR/CQcnhaoj+LWFnW6jLc48 dfjWGErLJfzJcECi7ZAWEXGMMueMhPHg5KaDh6l+AjQZ2ICqHXbCg9gXxLzsQIZn rBQbKAptx58vJjtsgShTiRT3dcz/GD2PH8X0IOhs8WvZ5rB2UZ9Xdy6Q60iqbs+Q OdV5soqvSobs9V/TuLwP =fXzr -----END PGP SIGNATURE----- --1vEdgMWljt97yA53--