From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756451AbZGOXNZ (ORCPT ); Wed, 15 Jul 2009 19:13:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755458AbZGOXNY (ORCPT ); Wed, 15 Jul 2009 19:13:24 -0400 Received: from an-out-0708.google.com ([209.85.132.247]:25283 "EHLO an-out-0708.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756366AbZGOXNY convert rfc822-to-8bit (ORCPT ); Wed, 15 Jul 2009 19:13:24 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=fdiC+WyhRawljj6frSOP5itHwI33nCKOEincciXC89Nb3dA/HfW9eI/xotj7DmhQwP 26QB6CFT1P5pJNpv59SHWoKHB1TmUlErQDi7wyX/8MoP3RK92DIQ12O13dQPDT41tEaz Pna1M0Ho5dXcra1l1b8eG5k2Ue2YDmBwIh7FM= MIME-Version: 1.0 In-Reply-To: <20090716001016.489fa970@lxorguk.ukuu.org.uk> References: <1247698965.3989.1.camel@dwillia2-linux.ch.intel.com> <20090716001016.489fa970@lxorguk.ukuu.org.uk> Date: Wed, 15 Jul 2009 19:13:23 -0400 Message-ID: <9e4733910907151613n777261e5k3e3c1cd646c7922a@mail.gmail.com> Subject: Re: Why do we probe option roms at 2K boundaries? From: Jon Smirl To: Alan Cox Cc: Dan Williams , Alan Cox , Linux Kernel Mailing List , Hans de Goede Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 15, 2009 at 7:10 PM, Alan Cox wrote: >> interrogating a data structure stored in option-rom memory.  My initial >> implementation involved blindly scanning from c0000 to f0000 in 512 byte >> increments.  Neil and others pointed out that this may not be a safe > > It isn't safe. If you hit certain ISA devices your system will drop dead. > OTOH I doubt anyone has an intel matrix raid controller and a WD80x3 on > the same box ;) Random link from google, slide 21 http://download.microsoft.com/download/9/8/f/98f3fe47-dfc3-4e74-92a3-088782200fe7/TWAR05005_WinHEC05.ppt PCI 3.0+ allows 512b alignment, but you must first make sure you are on a PCI 3.0+ system. > >> Recently Hans has been working to get Fedora up and running on a recent >> Intel software RAID platform and noticed that the option-rom is no >> longer visible with the 2K aligned scan.  I.e. he needed to make the >> following changes to the mdadm probe_roms() routine: > > Option ROMs should be 2K aligned. Is your data structure part of a ROM or > an actual ROM header ? > >> Is this safe?  Should the kernel be updated as well?  I am assuming that >> you were the one that originally introduced the 2K aligned scan with >> this commit from the historical git: > > Actually I don't think that was me, don't remember it anyway. > > The man to bug at the moment on ROM magic is probably H Peter Anvin > however. > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at  http://vger.kernel.org/majordomo-info.html > Please read the FAQ at  http://www.tux.org/lkml/ > -- Jon Smirl jonsmirl@gmail.com