From owner-svn-src-head@FreeBSD.ORG Sat Jun 6 16:03:47 2015 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id BB7F3242; Sat, 6 Jun 2015 16:03:47 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from bigwig.baldwin.cx (bigwig.baldwin.cx [IPv6:2001:470:1f11:75::1]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 96AE81098; Sat, 6 Jun 2015 16:03:47 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from ralph.baldwin.cx (pool-173-54-116-245.nwrknj.fios.verizon.net [173.54.116.245]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id 04F61B926; Sat, 6 Jun 2015 12:03:46 -0400 (EDT) From: John Baldwin To: Marcel Moolenaar Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r284078 - head/sys/dev/pci Date: Sat, 06 Jun 2015 12:03:38 -0400 Message-ID: <14005803.mtbqcRkBJG@ralph.baldwin.cx> User-Agent: KMail/4.14.3 (FreeBSD/10.1-STABLE; KDE/4.14.3; amd64; ; ) In-Reply-To: <201506061551.t56FpCbX013048@svn.freebsd.org> References: <201506061551.t56FpCbX013048@svn.freebsd.org> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.7 (bigwig.baldwin.cx); Sat, 06 Jun 2015 12:03:46 -0400 (EDT) X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.20 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: Sat, 06 Jun 2015 16:03:47 -0000 On Saturday, June 06, 2015 03:51:12 PM Marcel Moolenaar wrote: > Author: marcel > Date: Sat Jun 6 15:51:11 2015 > New Revision: 284078 > URL: https://svnweb.freebsd.org/changeset/base/284078 > > Log: > Don't return -10000 as the probe priority. That's lower than what > BUS_PROBE_HOOVER is. Drivers like proto(4), when compiled into the > kernel or preloaded, will render your system useless by virtue of > attaching to your PCI busses. > > Return BUS_PROBE_GENERIC instead. It's just the next priority up > from BUS_PROBE_HOOVER. No other meaning has been give to its use. > While BUS_PROBE_DEFAULT seems like a better candidate, it's hard > not to think that there must be some reason why these drivers > return -10000 in the first place. BUS_PROBE_DEFAULT would conflict with other drivers that are supposed to override these, such as acpi_pcib_pci which should override pci_pci for PCI-PCI bridges in the ACPI namespace. That driver currently hardcodes -1000 itself. :-/ Then there's pcibios_pcib_probe for the $PIR PCI-PCI bridge driver for when ACPI isn't present. It returns -2000. The MPTable PCI-PCI bridge driver returns -1000 like ACPI. That relative order (ACPI and MPTable are most preferred, then $PIR, then generic PCI-PCI) is important for PCI INTx interrupt routing on x86. In general any platform which knows better how to route INTx interrupts than the swizzle defined for add-on cards that pci_pci uses should override the pci_pci driver via a higher probe value. In this case simply using the stock BUS_PROBE values doesn't quite work since there isn't just DEFAULT/GENERIC, but on x86 you have at least three levels. Also, BUS_PROBE_GENERIC does have a meaning and it is well suited to these drivers. It is for drivers that match large classes of devices rather than specific devices. In PCI terms that would mean a device that matches on class/subclass rather than vendor/device ID (which is true of these bridge drivers. ignore_pci is a different animal). -- John Baldwin