From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752981AbYIXKYZ (ORCPT ); Wed, 24 Sep 2008 06:24:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751915AbYIXKYQ (ORCPT ); Wed, 24 Sep 2008 06:24:16 -0400 Received: from ns2.mvista.com ([63.81.120.155]:59639 "EHLO imap.sh.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751467AbYIXKYO (ORCPT ); Wed, 24 Sep 2008 06:24:14 -0400 Message-ID: <48DA1544.5010307@ru.mvista.com> Date: Wed, 24 Sep 2008 14:24:04 +0400 From: Sergei Shtylyov User-Agent: Thunderbird 2.0.0.16 (Windows/20080708) MIME-Version: 1.0 To: avorontsov@ru.mvista.com Cc: Andrew Morton , dbrownell@users.sourceforge.net, greg@kroah.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, leoli@freescale.com, timur@freescale.com Subject: Re: [PATCH 3/3] USB: driver for Freescale QUICC Engine USB Host Controller References: <20080918151659.GA20140@oksana.dev.rtsoft.ru> <20080918151746.GC31187@oksana.dev.rtsoft.ru> <20080919162324.e354ed2f.akpm@linux-foundation.org> <20080923183129.GA19024@oksana.dev.rtsoft.ru> <48D96052.6090005@ru.mvista.com> <48D9612D.7060601@ru.mvista.com> <20080923225730.GB13617@oksana.dev.rtsoft.ru> In-Reply-To: <20080923225730.GB13617@oksana.dev.rtsoft.ru> Content-Type: text/plain; charset=windows-1251; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello. Anton Vorontsov wrote: >>>>>> This controller does not integrate the root hub, so this driver also >>>>>> fakes one-port hub. External hub is required to support more than >>>>>> one device. >>>>>> >>>>>> ... >>>>>> >>>>>> >>>>>> >>>>> Please, no. >>>>> >>>>> >>>> What exactly 'no'? ;-) >>>> >>>> >>> No one-port hubs I guess -- they are pointless. Though e.g. MUSB >>> driver creates one -- I guess to impersonate a transaction translating >>> high-speed hub... >>> >>> >> ... then the root hub emulation is completely pointless. >> > > It isn't. We always should emulate the root hub. The root hub > is part and parcel of any USB Host. Even the one-port one. Hm, maybe that's what USB core thinks (because UHCI/OHCI/EHCI all have it) but e.g. MUSB doesn't have the root hub registers... I looked at the core and figured that USB core seems to use the root hub interface for port PM, etc. and expects it to bee present, so it seems unavoidable indeed... :-/ WBR, Sergei