From owner-svn-src-head@freebsd.org Fri Apr 24 18:13:52 2020 Return-Path: Delivered-To: svn-src-head@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 31E182BE4F7; Fri, 24 Apr 2020 18:13:52 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from smtp.freebsd.org (smtp.freebsd.org [96.47.72.83]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "smtp.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4982Nw0Nsdz3R5l; Fri, 24 Apr 2020 18:13:52 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from John-Baldwins-MacBook-Pro-164.local (unknown [IPv6:2601:648:8881:1e90:5c82:8b70:e0b1:b6aa]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) (Authenticated sender: jhb) by smtp.freebsd.org (Postfix) with ESMTPSA id 727BB1C844; Fri, 24 Apr 2020 18:13:51 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Subject: Re: svn commit: r360241 - head/sys/dev/ichiic To: Warner Losh , Andriy Gapon Cc: src-committers , svn-src-all , svn-src-head References: <202004240749.03O7nMSc066344@repo.freebsd.org> <32586115-2c82-2497-ba4c-b3471887518d@FreeBSD.org> <02449f05-6c43-9cb0-b427-34034a3c358f@FreeBSD.org> From: John Baldwin Autocrypt: addr=jhb@FreeBSD.org; keydata= mQGiBETQ+XcRBADMFybiq69u+fJRy/0wzqTNS8jFfWaBTs5/OfcV7wWezVmf9sgwn8TW0Dk0 c9MBl0pz+H01dA2ZSGZ5fXlmFIsee1WEzqeJzpiwd/pejPgSzXB9ijbLHZ2/E0jhGBcVy5Yo /Tw5+U/+laeYKu2xb0XPvM0zMNls1ah5OnP9a6Ql6wCgupaoMySb7DXm2LHD1Z9jTsHcAQMD /1jzh2BoHriy/Q2s4KzzjVp/mQO5DSm2z14BvbQRcXU48oAosHA1u3Wrov6LfPY+0U1tG47X 1BGfnQH+rNAaH0livoSBQ0IPI/8WfIW7ub4qV6HYwWKVqkDkqwcpmGNDbz3gfaDht6nsie5Z pcuCcul4M9CW7Md6zzyvktjnbz61BADGDCopfZC4of0Z3Ka0u8Wik6UJOuqShBt1WcFS8ya1 oB4rc4tXfSHyMF63aPUBMxHR5DXeH+EO2edoSwViDMqWk1jTnYza51rbGY+pebLQOVOxAY7k do5Ordl3wklBPMVEPWoZ61SdbcjhHVwaC5zfiskcxj5wwXd2E9qYlBqRg7QeSm9obiBCYWxk d2luIDxqaGJARnJlZUJTRC5vcmc+iGAEExECACAFAkTQ+awCGwMGCwkIBwMCBBUCCAMEFgID AQIeAQIXgAAKCRBy3lIGd+N/BI6RAJ9S97fvbME+3hxzE3JUyUZ6vTewDACdE1stFuSfqMvM jomvZdYxIYyTUpC5Ag0ERND5ghAIAPwsO0B7BL+bz8sLlLoQktGxXwXQfS5cInvL17Dsgnr3 1AKa94j9EnXQyPEj7u0d+LmEe6CGEGDh1OcGFTMVrof2ZzkSy4+FkZwMKJpTiqeaShMh+Goj XlwIMDxyADYvBIg3eN5YdFKaPQpfgSqhT+7El7w+wSZZD8pPQuLAnie5iz9C8iKy4/cMSOrH YUK/tO+Nhw8Jjlw94Ik0T80iEhI2t+XBVjwdfjbq3HrJ0ehqdBwukyeJRYKmbn298KOFQVHO EVbHA4rF/37jzaMadK43FgJ0SAhPPF5l4l89z5oPu0b/+5e2inA3b8J3iGZxywjM+Csq1tqz hltEc7Q+E08AAwUIAL+15XH8bPbjNJdVyg2CMl10JNW2wWg2Q6qdljeaRqeR6zFus7EZTwtX sNzs5bP8y51PSUDJbeiy2RNCNKWFMndM22TZnk3GNG45nQd4OwYK0RZVrikalmJY5Q6m7Z16 4yrZgIXFdKj2t8F+x613/SJW1lIr9/bDp4U9tw0V1g3l2dFtD3p3ZrQ3hpoDtoK70ioIAjjH aIXIAcm3FGZFXy503DOA0KaTWwvOVdYCFLm3zWuSOmrX/GsEc7ovasOWwjPn878qVjbUKWwx Q4QkF4OhUV9zPtf9tDSAZ3x7QSwoKbCoRCZ/xbyTUPyQ1VvNy/mYrBcYlzHodsaqUDjHuW+I SQQYEQIACQUCRND5ggIbDAAKCRBy3lIGd+N/BCO8AJ9j1dWVQWxw/YdTbEyrRKOY8YZNwwCf afMAg8QvmOWnHx3wl8WslCaXaE8= Message-ID: Date: Fri, 24 Apr 2020 11:13:48 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Apr 2020 18:13:52 -0000 On 4/24/20 9:57 AM, Warner Losh wrote: > On Fri, Apr 24, 2020 at 10:07 AM Andriy Gapon wrote: >> Let's use ig4 as an example. >> Across its source files we had the following DRIVER_MODULE declarations: >> DRIVER_MODULE(ig4iic, acpi, ... -- in ig4_acpi.c >> DRIVER_MODULE(iicbus, ig4iic, ... -- in ig4_iic.c >> DRIVER_MODULE(acpi_iicbus, ig4iic, ... -- in ig4_iic.c >> The first one is needed to register ig4iic driver under acpi bus. Other >> two are >> needed to register iicbus and acpi_iicbus drivers under ig4iic bus. >> The order is not explicitly defined, so the corresponding declaration can >> be >> processed in any order when ig4.ko is loaded and so the corresponding >> devclass_add_driver() can be called in any order. >> > > It's a bug in newbus if that matters. I'll grant that it does today, but it > shouldn't. In the past we've worked around this issue in a number of > different ways (including having 3 different modules with the order encoded > into those modules). It also indicates, perhaps, bugs in the iic acpi > enumeration stuff, but that's a harder case to make without more careful > study since I know that acpi_iic works around the bit of a mismatch between > newbus' device model and ACPI's. FWIW, this is a longstanding bug, and it is the reason DRIVER_MODULE_ORDERED exists[1], precisely so you can get all the child driver module's registered first and have the "top-most" (in the hierarchy) driver register last so that all the others are ready as new child devices are created. The _ORDERED solution is the only one I'm aware of that we have used for a single module containing multiple drivers. It may be that we have split up into tiny modules in the past, but that solution is probably worse as the dependencies are usually the wrong way around (the "leaf" drivers probably depend on the parent drivers so they get loaded in the exact wrong order for this case where you want all the leaf drivers registered before an instance of the parent driver attaches) 1: https://svnweb.freebsd.org/base?view=revision&revision=225079 -- John Baldwin