From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752931Ab0FMAQq (ORCPT ); Sat, 12 Jun 2010 20:16:46 -0400 Received: from terminus.zytor.com ([198.137.202.10]:50422 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752868Ab0FMAQp (ORCPT ); Sat, 12 Jun 2010 20:16:45 -0400 Message-ID: <4C14235B.7030605@zytor.com> Date: Sat, 12 Jun 2010 17:16:27 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-3.fc13 Thunderbird/3.0.4 MIME-Version: 1.0 To: Josh Triplett CC: Ben Hutchings , x86@kernel.org, 584846@bugs.debian.org, LKML Subject: Re: Bug#584846: Detects only 64MB and fails to boot on Intel Green City board if e820 hooked by GRUB2 References: <20100612060322.29053.94187.reportbug@feather> <1276351120.14011.194.camel@localhost> <4C13D1E7.7060604@zytor.com> <20100612185538.GA4511@feather> <4C13F102.7000509@zytor.com> <20100612222634.GA1785@feather> <4C141214.5050601@zytor.com> <20100613000742.GA3469@feather> In-Reply-To: <20100613000742.GA3469@feather> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/12/2010 05:07 PM, Josh Triplett wrote: > On Sat, Jun 12, 2010 at 04:02:44PM -0700, H. Peter Anvin wrote: >> On 06/12/2010 03:26 PM, Josh Triplett wrote: >>> >>> Everything looks identical except for the region GRUB hooked right below >>> the first reserved region; the unhooked version has available memory >>> from 0-0x9cbf0, and the hooked version has available memory from >>> 0-0x9cba0, then reserved from 0x9cba0-0x9cbec, then 4 bytes of available >>> memory, and then the same reserved region as before. >> >> Actually... are both these done by chainloading Grub (with and without >> mapping), or is the unhooked done without chainloading Grub at all? >> >> To me it looks like something is chaining INT 15h even in the >> "unchained" case... > > The "unhooked" case still chainloaded from GRUB, just without calling > drivemap and thus without hooking anything. I can test without > chainloading from GRUB, though to the best of my knowledge GRUB doesn't > hook int 15 unless it needs to intercept e820 (and e801 and 88). > > - Josh Triplett Well *something* is... and it might not be Grub but one of the expansion ROMs. If so, the problem is probably Grub stepping on the expansion ROM by not honoring FBM. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.