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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1A42EC4332F for ; Mon, 25 Oct 2021 13:20:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EFC9660F46 for ; Mon, 25 Oct 2021 13:20:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233480AbhJYNWf (ORCPT ); Mon, 25 Oct 2021 09:22:35 -0400 Received: from new3-smtp.messagingengine.com ([66.111.4.229]:33687 "EHLO new3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230085AbhJYNWe (ORCPT ); Mon, 25 Oct 2021 09:22:34 -0400 Received: from compute6.internal (compute6.nyi.internal [10.202.2.46]) by mailnew.nyi.internal (Postfix) with ESMTP id 08F7D580571; Mon, 25 Oct 2021 09:20:09 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute6.internal (MEProxy); Mon, 25 Oct 2021 09:20:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=stwcx.xyz; h= date:from:to:cc:subject:message-id:references:mime-version :content-type:in-reply-to; s=fm3; bh=rOeGD7a5iJXgcSU4RpNH06SfRz+ WF+JeakPDiY4K90A=; b=bJolnp7Yx+sgYjFOKpPJosObmpUcAyzXPZ1t4JciNVY MGGBIfg+urDV3ZCWgvrOBdD21CQNLVhh+jUqI1ZrLbJJKzTK6dSoQ23Exgg9b+Cz catmuS2kyUohmH8xYN7wvYgWypKkcmoa6/tj9zq+16iM458HK8HorsCH5vMZGbGz Ek1XePVkrPuTqco19E5coWOwiX6dCOZklZJfpNZ2U/Z0XrimFn6rDQUgl1p7/7kH pUVw7m1NVMTutufkRhpVxxbYqvhHqm/Lb5leXteCQpf6YIN2sIliVl93s6BHnvmr 5DcwmtVuGI1/tLq5FlIkiTHbzP8mHYfjZqXvAUrsAig== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm1; bh=rOeGD7 a5iJXgcSU4RpNH06SfRz+WF+JeakPDiY4K90A=; b=PQwv4wzc3KEsYUqSwJ5i+z fJmk+/sOcY6wxVUONUkZadm2RDMRJ/Lzk/2yRCUbtPZ1h3FfnE6Xr23glUp388kA 66CDqXfUlO081TsYIQO23jbkrOkc5nD+wPhjLXMXjB0+wiUU1sf8daBdE1SW+LED By1qyli5NfsJHHufdpBH75BY7Wc9f+vmmPAgXJu/j9kpGlNGmyzIL2Baj2/vhp2u mYfrykIcVgaf6o7/OttF/RcCcUM571DXXxOn3hycR4v4keWol/YLxT9x5MYBHpWV ztCn8JEjNnkSDWFqxcnYAaj9+RhAt7ROJQMIwAsNC2wCJtCtJUv0BgQk+9WyQJ2w == X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvtddrvdefhedgieduucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne gfrhhlucfvnfffucdljedtmdenucfjughrpeffhffvuffkfhggtggujgesghdtreertddt vdenucfhrhhomheprfgrthhrihgtkhcuhghilhhlihgrmhhsuceophgrthhrihgtkhessh htfigtgidrgiihiieqnecuggftrfgrthhtvghrnhepgeehheefffegkeevhedthffgudfh geefgfdthefhkedtleffveekgfeuffehtdeinecuvehluhhsthgvrhfuihiivgeptdenuc frrghrrghmpehmrghilhhfrhhomhepphgrthhrihgtkhesshhtfigtgidrgiihii X-ME-Proxy: Received: by mail.messagingengine.com (Postfix) with ESMTPA; Mon, 25 Oct 2021 09:20:06 -0400 (EDT) Date: Mon, 25 Oct 2021 08:20:05 -0500 From: Patrick Williams To: Andy Shevchenko Cc: Greg Kroah-Hartman , Frank Rowand , Zev Weiss , kvm@vger.kernel.org, "Rafael J. Wysocki" , Kirti Wankhede , Jeremy Kerr , Rajat Jain , Jianxiong Gao , Dave Jiang , Saravana Kannan , Mauro Carvalho Chehab , openbmc@lists.ozlabs.org, devicetree@vger.kernel.org, Konrad Rzeszutek Wilk , Alex Williamson , Rob Herring , Bhaskar Chowdhury , Thomas Gleixner , Andrew Jeffery , Cornelia Huck , linux-kernel@vger.kernel.org, Vinod Koul , dmaengine@vger.kernel.org Subject: Re: [PATCH 4/5] driver core: inhibit automatic driver binding on reserved devices Message-ID: References: <20211022020032.26980-5-zev@bewilderbeest.net> <627101ee-7414-57d1-9952-6e023b8db317@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="190gZ0lVdnV/mRoG" Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --190gZ0lVdnV/mRoG Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Oct 25, 2021 at 03:58:25PM +0300, Andy Shevchenko wrote: > On Mon, Oct 25, 2021 at 06:44:26AM -0500, Patrick Williams wrote: > > On Mon, Oct 25, 2021 at 08:15:41AM +0200, Greg Kroah-Hartman wrote: > > > On Mon, Oct 25, 2021 at 12:38:08AM -0500, Frank Rowand wrote: > > > > On 10/23/21 3:56 AM, Greg Kroah-Hartman wrote: > > =20 > > > We have the bind/unbind ability today, from userspace, that can contr= ol > > > this. Why not just have Linux grab the device when it boots, and then > > > when userspace wants to "give the device up", it writes to "unbind" in > > > sysfs, and then when all is done, it writes to the "bind" file and th= en > > > Linux takes back over. > > >=20 > > > Unless for some reason Linux should _not_ grab the device when bootin= g, > > > then things get messier, as we have seen in this thread. > >=20 > > This is probably more typical on a BMC than atypical. The systems ofte= n require > > the BMC (running Linux) to be able to reboot independently from the man= aged host > > (running anything). In the example Zev gave, the BMC rebooting would r= ip away > > the BIOS chip from the running host. > >=20 > > The BMC almost always needs to come up in a "I don't know what could po= ssibly be > > going on in the system" state and re-discover where the system was left= off. >=20 > Isn't it an architectural issue then? I'm not sure what "it" you are referring to here. I was trying to explain why starting in "bind" state is not a good idea for= a BMC in most of these cases where we want to be able to dynamically add a de= vice. --=20 Patrick Williams --190gZ0lVdnV/mRoG Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEBGD9ii4LE9cNbqJBqwNHzC0AwRkFAmF2rwMACgkQqwNHzC0A wRk9Jw//e7gf0atu+Jk54NpG8wRJo875a0T6uIfxMH3+j8JgwRu5aEeH4Z4V02pk s2Zwvy4l6o0lIcgLCAWYQfpmV5E6vNBSn1ymXNW0RpY7ZhheqKKi2FFDuJwxgIgE j+IZUGzSXYD5Ttwf/FPG98BX7/cdlJGsvoMpjrQoegPC8e6CYVnOpkGF0rjZJSid DXopkEnAhkRURQlh46yH1j83UZOFxDfOY3KP7XLcc4aPYBYm+y76WbZQON8aNdZG o1uOYbSKxaZ+z6ZDyPWD1GA46ZrpYpEUeTypmW9a1g9d6ot45oK6I9lp+qRGwWoy 4spswa4MMv6BqcYnw/iXLpFQOi8h/7XO49yuF/O6Bu3b9xOvvfduxGWMervBarbs q+SDU1k6U23uLlp40hmTzmFxdnH4YlB1/vLdP5aIsaVsWzyzYIh1AP3aIHmPFpwI DRPQ3WZu792khszBv/SNDkGuO3SJpgXYT+eakB1TofbkBaPtbjK88wmfs5rh1kyW QUrQUpQIuUDmhzyb8ELGFWb4/cWHYiKKyKV6+ynKXhzdXLGUQxslR1uM687DJxcI gmhK+d2uLQh+UHRDyZqH28oUmfpc0V5TukpV2PkBi0Nm9K6X6baYNsnAOwLAB5ya 5F81+hR5s1AQFaGPxqQzTSsbh33SjZyXG/5kMtLr2xnaHAToxrQ= =r9se -----END PGP SIGNATURE----- --190gZ0lVdnV/mRoG--