Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966097Ab2EORcs (ORCPT ); Tue, 15 May 2012 13:32:48 -0400 Received: from mail-vb0-f46.google.com ([209.85.212.46]:45450 "EHLO mail-vb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966038Ab2EORcr convert rfc822-to-8bit (ORCPT ); Tue, 15 May 2012 13:32:47 -0400 MIME-Version: 1.0 In-Reply-To: <20120514064615.GB26605@richard> References: <20120410090306.GA7056@richard> <20120422155202.GA13540@richard> <4F95B17B.3030401@redhat.com> <20120514015536.GA3331@richard> <20120514064615.GB26605@richard> Date: Tue, 15 May 2012 10:32:46 -0700 X-Google-Sender-Auth: 6j8QvFuElUGqaLYn6G3bWbJWyF0 Message-ID: Subject: Re: One problem in reassign pci bus number? From: Yinghai Lu To: Richard Yang Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2780 Lines: 68 On Sun, May 13, 2012 at 11:46 PM, Richard Yang wrote: > On Sun, May 13, 2012 at 10:40:41PM -0700, Yinghai Lu wrote: >>On Sun, May 13, 2012 at 6:55 PM, Richard Yang >> wrote: >>> On Mon, Apr 23, 2012 at 03:46:03PM -0400, Don Dutile wrote: >>>>On 04/22/2012 11:52 AM, Richard Yang wrote: >>>>>All, >>>>> >>>>>I am reading the pci_scan_bridge() and not sure what will happen in >>>>>following situation. >>>>> >>>>>Suppose the kernel is not passed the pci=assign-busses. >>>>> >>>>>Below is a picture about the pci system. >>>>> >>>>> ? ? ? ? ? ? ? ? ? ?+-------+ >>>>> ? ? ? ? ? ? ? ? ? ?| ? ? ? | root bridge(0,255) >>>>> ? ? ? ? ? ? ? ? ? ?+---+---+ >>>>> ? ? ? ? ? ? ? ? ? ? ? ?| ? ? ? ? ?Bus 0 >>>>> ? ? ? -----+-----------+------------------------------+-- >>>>> ? ? ? ? ? ?| ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?| >>>>> ? ? ? ? ? ?| ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?| >>>>> ? ? ? ? ? ?| ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?| >>>>> ? ? ? +----+----+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? +-----+-----+ >>>>> ? ? ? | ? ? ? ? | ?B1(1,15) ? ? ? ? ? ? ? ? ? ? | ? ? ? ? ? |B2(16,28) >>>>> ? ? ? +----+----+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? +-----+-----+ >>>>> ? ? ? ? ? ?| ?Bus 1 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? | ? ?Bus 16 >>>>> ? ? ? -----+----------------------- ? ? ? ? ----------+---------------- >>>>> ? ? ? ? ? ? ? ? ? ? ? ? ? ? | >>>>> ? ? ? ? ? ? ? ? ? ? ? ?+----+----+ >>>>> ? ? ? ? ? ? ? ? ? ? ? ?| ? ? ? ? | B3 >>>>> ? ? ? ? ? ? ? ? ? ? ? ?+---------+ >>>>> >>>>>Suppose B1 and B2 works fine with the BIOS, which get the right bus >>>>>number and range. >>>>> >>>>>B3 does not works fine with the BIOS, which doesn't get the bus number. >>>>> >>> Take my original question. >>> >>> B3 doesn't get the bus number, which its parent doesn't have free bus >>> number and there is no gap between B1 and B2. >>> >>> So in this case, the probe_resource() can't find bus number for B3. >>> Then cause pci_bridge_probe_busn_res() return non-zero. >>> >>> Then B3 couldn't work fine? >> >>B3 is on Bus 1? B3 is the one of bridges on Bus1? > No, ?I omit other bridges on Bus#1. > They will occupy bus number 2-15, which is calculated by BIOS and set to > bridge's configuration space. with that new condition, probe_resource will return zero. for those kind of case: 1. use echo 1 > /sys .../remove to remove devices under Bridge2. 2. use setpci to change bus register of bridge2 to move high to make more space for bridge 1. 3. rescan bridge 1 and bridge 2. Yinghai -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/