From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4ECB0C43462 for ; Tue, 6 Apr 2021 13:44:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2FCE16113E for ; Tue, 6 Apr 2021 13:44:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344675AbhDFNor (ORCPT ); Tue, 6 Apr 2021 09:44:47 -0400 Received: from lizzard.sbs.de ([194.138.37.39]:43233 "EHLO lizzard.sbs.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344659AbhDFNon (ORCPT ); Tue, 6 Apr 2021 09:44:43 -0400 Received: from mail2.sbs.de (mail2.sbs.de [192.129.41.66]) by lizzard.sbs.de (8.15.2/8.15.2) with ESMTPS id 136DhfCQ018008 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 6 Apr 2021 15:43:41 +0200 Received: from md1za8fc.ad001.siemens.net ([167.87.42.66]) by mail2.sbs.de (8.15.2/8.15.2) with ESMTP id 136De2KZ031989; Tue, 6 Apr 2021 15:40:02 +0200 Date: Tue, 6 Apr 2021 15:40:01 +0200 From: Henning Schild To: "Enrico Weigelt, metux IT consult" Cc: Bjorn Helgaas , Andy Shevchenko , Wolfram Sang , Jean Delvare , "Lee Jones" , Tan Jui Nee , "Jim Quinlan" , Jonathan Yong , Bjorn Helgaas , , , , Jean Delvare , Peter Tyser , Subject: Re: [PATCH v1 3/7] PCI: New Primary to Sideband (P2SB) bridge support library Message-ID: <20210406154001.3eec0698@md1za8fc.ad001.siemens.net> In-Reply-To: <3f33a178-3002-e93e-89f1-8cf05097da25@metux.net> References: <20210309014221.GA1831206@bjorn-Precision-5520> <20210309094252.396b7f2d@md1za8fc.ad001.siemens.net> <3f33a178-3002-e93e-89f1-8cf05097da25@metux.net> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org Am Fri, 2 Apr 2021 15:09:12 +0200 schrieb "Enrico Weigelt, metux IT consult" : > On 09.03.21 09:42, Henning Schild wrote: > > > The device will respond to MMIO while being hidden. I am afraid > > nothing stops a collision, except for the assumption that the BIOS > > is always right and PCI devices never get remapped. But just > > guessing here. > > What could go wrong if it is remapped, except that this driver would > write to the wrong mmio space ? > > If it's unhidden, pci-core should see it and start the usual probing, > right ? I have seen this guy exposed to Linux on coreboot machines. No issues. But i can imagine BIOSs that somehow make use of the device and assume it wont move. So we would at least need a parameter to allow keeping that device hidden, or "fixed" in memory. Henning > > --mtx >