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 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2091DC433F5 for ; Thu, 6 Jan 2022 18:14:16 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7CE4210E750; Thu, 6 Jan 2022 18:14:15 +0000 (UTC) Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by gabe.freedesktop.org (Postfix) with ESMTPS id 449F010E750 for ; Thu, 6 Jan 2022 18:14:14 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id E4BAFB822E4; Thu, 6 Jan 2022 18:14:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A780C36AEB; Thu, 6 Jan 2022 18:14:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1641492850; bh=pk9c3vFsS24A9H9YRNmuoLU04tTgveyiSfxz/RguLrg=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=tWL9ah320xPJ7ZLvQrLFkjIeV1LTlPrJ2qSY/t0fKFbU+5MxnpWBBUesVfIjO0xOO l+Yvi8TANgRjNK2vReZYRlLqehfzP4qE2oNJarfvWixIS0OfQkuKWpI6rrQEfWGn25 oroVHI/IQA8JEpMkHqxWMkHxAKg+IVXn/Zqji7RoVtpWyymeRt5WcM4qay0A7EFOWe jnI4JpbaAmAttF9a/Yhl/wWUUgx6A1s8zF9Wpc8ft5Y9hFSMLv91rRujQQ/od6scnA LsHiF+8iYMGoQ6RcvIn/+ZU8WqHN0Y3LnsXMJdYHRbXi/+K/WGfnGi+pM9zExj10bs +smYL/+iBYHZg== Date: Thu, 6 Jan 2022 12:14:09 -0600 From: Bjorn Helgaas To: John Garry Subject: Re: [RFC 01/32] Kconfig: introduce and depend on LEGACY_PCI Message-ID: <20220106181409.GA297735@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <74bf4fde-3972-1c36-ca04-58089da0d82b@huawei.com> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-fbdev@vger.kernel.org, linux-pci@vger.kernel.org, Wim Van Sebroeck , Ettore Chimenti , linux-ide@vger.kernel.org, Albert Ou , Guo Ren , linux-i2c@vger.kernel.org, linux-riscv@lists.infradead.org, Vincent Chen , Jiri Slaby , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Hannes Reinecke , Michael Grzeschik , linux-scsi@vger.kernel.org, Sumit Saxena , Bartosz Golaszewski , Sathya Prakash , Jesse Brandeburg , linux-csky@vger.kernel.org, Kashyap Desai , Nilesh Javali , intel-wired-lan@lists.osuosl.org, linux-serial@vger.kernel.org, GR-QLogic-Storage-Upstream@marvell.com, Jakub Kicinski , MPT-FusionLinux.pdl@broadcom.com, "James E.J. Bottomley" , Guenter Roeck , linux-media@vger.kernel.org, Jaroslav Kysela , Jean Delvare , linux-watchdog@vger.kernel.org, Arnd Bergmann , Niklas Schnelle , Jouni Malinen , Suganath Prabu Subramani , Kalle Valo , linux-input@vger.kernel.org, linux-spi@vger.kernel.org, linux-gpio@vger.kernel.org, Ian Abbott , Mark Brown , Greentime Hu , Paul Walmsley , Bjorn Helgaas , Mauro Carvalho Chehab , megaraidlinux.pdl@broadcom.com, Teddy Wang , linux-hwmon@vger.kernel.org, Arnd Bergmann , Karsten Keil , Sreekanth Reddy , "Martin K. Petersen" , Nick Hu , Sudip Mukherjee , Shivasharan S , Greg Kroah-Hartman , dri-devel@lists.freedesktop.org, Dmitry Torokhov , linux-wireless@vger.kernel.org, Takashi Iwai , "David S. Miller" , H Hartley Sweeten , Palmer Dabbelt , Forest Bond , netdev@vger.kernel.org, Hans Verkuil , Tony Nguyen , Damien Le Moal Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Thu, Jan 06, 2022 at 05:41:00PM +0000, John Garry wrote: > On 05/01/2022 19:47, Bjorn Helgaas wrote: > > IMO inb() should > > be present but do something innocuous like return ~0, as it would if > > I/O port space is supported but there's no device at that address. > > > > [1]https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/scsi/megaraid.c?id=v5.15#n4210 > > > > That driver would prob not be used on systems which does not support PIO, > and so could have a HAS_IOPORT dependency. But it is not strictly necessary. I don't want the path of "this driver isn't needed because the device is unlikely to be used on this arch." Maybe it's not _always_ possible, but if the device can be plugged into the platform, I think we should be able to build the driver for it. If the device requires I/O port space and the platform doesn't support it, the PCI core or the driver should detect that and give a useful diagnostic. Bjorn