From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Cox Subject: Re: Fw: [PATCH]: Correctly locate RSDP in EBDA Date: Tue, 26 Jul 2005 10:53:57 +0100 Message-ID: <1122371637.1101.12.camel@localhost.localdomain> References: <20050725151313.730257bd.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20050725151313.730257bd.akpm-3NddpPZAyC0@public.gmane.org> Sender: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: Andrew Morton Cc: acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, "Udo A. Steinberg" List-Id: linux-acpi@vger.kernel.org On Llu, 2005-07-25 at 15:13 -0700, Andrew Morton wrote: > * Scan memory looking for the RSDP signature. First search EBDA (low > * memory) paragraphs and then search upper memory (E0000-FFFFF). > */ > - rsdp_phys = acpi_scan_rsdp (0, 0x400); > + rsdp_phys = acpi_scan_rsdp (*(u16*) 0x40E << 4, 0x400); Close but no cookie. You need to read 0x40E from physical memory not kernel virtual address space. It may also be zero which indicates that there isn't an EBDA, sometimes interpreted as an EBDA in the top 1K or so. ------------------------------------------------------- SF.Net email is sponsored by: Discover Easy Linux Migration Strategies from IBM. Find simple to follow Roadmaps, straightforward articles, informative Webcasts and more! Get everything you need to get up to speed, fast. http://ads.osdn.com/?ad_id=7477&alloc_id=16492&op=click