From owner-freebsd-hackers@FreeBSD.ORG Tue Aug 24 15:37:23 2010 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 10FAC106566B for ; Tue, 24 Aug 2010 15:37:23 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id D2A208FC12 for ; Tue, 24 Aug 2010 15:37:22 +0000 (UTC) Received: from bigwig.baldwin.cx (66.111.2.69.static.nyinternet.net [66.111.2.69]) by cyrus.watson.org (Postfix) with ESMTPSA id 631F146B92; Tue, 24 Aug 2010 11:37:22 -0400 (EDT) Received: from jhbbsd.localnet (smtp.hudson-trading.com [209.249.190.9]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id 7C3CD8A03C; Tue, 24 Aug 2010 11:37:21 -0400 (EDT) From: John Baldwin To: "M. Warner Losh" Date: Tue, 24 Aug 2010 10:09:46 -0400 User-Agent: KMail/1.13.5 (FreeBSD/7.3-CBSD-20100819; KDE/4.4.5; amd64; ; ) References: <201008170907.20593.jhb@freebsd.org> <201008171615.21103.jhb@freebsd.org> <20100823.220945.232861953240012158.imp@bsdimp.com> In-Reply-To: <20100823.220945.232861953240012158.imp@bsdimp.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201008241009.46624.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.0.1 (bigwig.baldwin.cx); Tue, 24 Aug 2010 11:37:21 -0400 (EDT) X-Virus-Scanned: clamav-milter 0.95.1 at bigwig.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-2.6 required=4.2 tests=AWL,BAYES_00 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on bigwig.baldwin.cx Cc: yanegomi@gmail.com, freebsd-hackers@freebsd.org Subject: Re: Why doesn't ppc(4) check non-ENXIO failures during probe? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 24 Aug 2010 15:37:23 -0000 On Tuesday, August 24, 2010 12:09:45 am M. Warner Losh wrote: > In message: <201008171615.21103.jhb@freebsd.org> > John Baldwin writes: > : > So more or less it's for BIOSes with ISA that doesn't feature plug > : > and play (286s, 386s, some 486s?)? Just trying to fill in the gap :). > : > : Yes, it may perhaps still be useful for some x86 embedded systems, though > : it is doubtful that those would use a ppc(4) device perhaps. > > Many embedded x86 systems use ppc(4) as a DIO port. ppi attaches to > it and can be used to frob bits. > > These days, of course, almost all boards have ACPI, so that means they > get enumerated that way. Only boards that don't run windows might not > have ACPI, in which case the devices are usually enumerated via > PNPBIOS. But not always, since those boards tend to have the buggiest > BIOSes on the planet in this area. Hints are needed on a few of these > boards since nothing else will work. And they have Atom processors on > them... The specific code I am referring to is the code in ppc_isa_probe() that tries to auto-identify a ppc port by poking at various I/O ports directly. It is not enabled by default. You'd have to have a ppc hint that did not include an I/O port for this code to be triggered I think as it only gets executed if a ppc(4) device does not have an I/O port resource from ACPI/PnPBIOS/hints. I was mostly thinking of this in terms of ISA cards, and I doubt that even modern embedded systems have ISA slots. :) -- John Baldwin