Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754062AbcCVGkw (ORCPT ); Tue, 22 Mar 2016 02:40:52 -0400 Received: from mga14.intel.com ([192.55.52.115]:4133 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751160AbcCVGkn (ORCPT ); Tue, 22 Mar 2016 02:40:43 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,375,1455004800"; d="asc'?scan'208";a="929167263" From: Felipe Balbi To: John Youn , Roger Quadros , John Youn Cc: "nsekhar\@ti.com" , "linux-usb\@vger.kernel.org" , "linux-kernel\@vger.kernel.org" Subject: Re: [PATCH 1/2] usb: dwc3: core: Introduce dwc3_device_reinit() In-Reply-To: <56F03FD7.30202@synopsys.com> References: <1458133551-3071-1-git-send-email-rogerq@ti.com> <1458133551-3071-2-git-send-email-rogerq@ti.com> <87r3fah8h3.fsf@intel.com> <87lh5ih6hs.fsf@intel.com> <56EC5452.8030509@synopsys.com> <56F03FD7.30202@synopsys.com> User-Agent: Notmuch/0.21 (http://notmuchmail.org) Emacs/25.0.90.3 (x86_64-pc-linux-gnu) Date: Tue, 22 Mar 2016 08:39:34 +0200 Message-ID: <874mbzyq1l.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: 3131 Lines: 89 --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Hi, John Youn writes: > [ text/plain ] > On 3/18/2016 12:17 PM, John Youn wrote: >> On 3/16/2016 6:56 AM, Felipe Balbi wrote: >>> >>> heh, +john >>> >>> Felipe Balbi writes: >>>> [ text/plain ] >>>> >>>> Hi, >>>> >>>> Roger Quadros writes: >>>>> [ text/plain ] >>>>> We will need this function for a workaround. >>>>> The function issues a softreset only to the device >>>>> controller and performs minimal re-initialization >>>>> so that the device controller can be usable. >>>>> >>>>> As some code is similar to dwc3_core_init() take out >>>>> common code into dwc3_get_gctl_quirks(). >>>>> >>>>> We add a new member (prtcap_mode) to struct dwc3 to >>>>> keep track of the current mode in the PRTCAPDIR register. >>>>> >>>>> Signed-off-by: Roger Quadros >>>> >>>> I must say, I don't like this at all :-p There's ONE known silicon whi= ch >>>> needs this because of a poor silicon integration which took an IP with= a >>>> known erratum where it can't be made to work on lower speeds and STILL >>>> was integrated without a superspeed PHY. >>>> >>>> There's a reason why I never tried to push this upstream myself ;-) >>>> >>>> I'm really thinking we might be better off adding a quirk flag to skip >>>> the metastability workaround and allow this ONE silicon to set the >>>> controller to lower speed. >>>> >>>> John, can you check with your colleagues if we would ever fall into >>>> STAR#9000525659 if we set maximum speed to high speed during driver >>>> probe and never touch it again ? I would assume we don't really fall >>>> into the metastability workaround, right ? We're not doing any sort of >>>> PM for dwc3... >>>> > > Hi Felipe, > > Do you mean to keep DCFG.speed to SS and set dwc->maximum_speed to HS? > I don't see an issue with that as long as we always ignore > dwc->maximum_speed when programming DCFG.speed for all affected > versions of the core. As long as the DCFG.speed =3D SS, you should not > hit the STAR. I actually mean changing DCFG.speed during driver probe and never touching it again. Would that still cause problems ? =2D-=20 balbi --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJW8OinAAoJEIaOsuA1yqREJUUP/jomwz7HHhNCuudjPH8XX85U fCso5NUml/B6Um0g4luushusu2hgapn+Hw8ugGUz+dn9uD1Uqm1y82hMWpMQF3/l uOEvGPog0/qetIMRAO7ydjWhAfh9S2Jyn3bO3HD/JMwq3fB/SvuUkc5os+zk4dAY LYDMT1+w3f4WystiRM9ZbpYTpqHvi5WgTllWBHPIxzsdNIav0HktmiMDTdM4w+O/ z8zp2lOvqI8qWDXkASyGDEO/CuaDzH2oVuS/9r1IdjnpQwb7Xy+snfYw3TwParUt LqVt9nCI+pxi6IuDS3BKSnM2hSL5HfNDKnKcUBRJSzL1NvRD9bEHEB/0/NxCI3LO a2Drt6oQO9kOkFWdA/unE63jAZf8VcGQ5DT/kLXnPU4mk9OXz+c+8oYqnDrd05fE vEwQuu/sVtBaDqJfDa2C7RKM3BjyZ+Ionj4MJo0TDdfdQ+fUnbHQ0/M+BlIb1Hp5 RQTX3YI6m56Dh6cq3qEfAvzvOxAcUV6AxwjqpAra25Ea9BvfS9hsEwClTASQRMA8 xHHoZGLPYzTplUKgOPrM+zu64eEQjz90DLy4mknw2lgt01BBibNVyp5VPYQO7PnQ SUNtRSmAeRFmquvFkApwopzMmQxwRJSzqVDi7AirmAL43tEY26ryXapF785q8iI4 UbrKuFy9jd5kTDzPVjrg =StvO -----END PGP SIGNATURE----- --=-=-=--