From: Andrew Morton <akpm-3NddpPZAyC0@public.gmane.org>
To: acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Cc: "Udo A. Steinberg"
<us15-IG//nw+yl+iQIjdd1DhZXWfrygkm6VTR@public.gmane.org>
Subject: Fw: [PATCH]: Correctly locate RSDP in EBDA
Date: Mon, 25 Jul 2005 15:13:13 -0700 [thread overview]
Message-ID: <20050725151313.730257bd.akpm@osdl.org> (raw)
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Begin forwarded message:
Date: Wed, 20 Jul 2005 17:42:07 +0200
From: "Udo A. Steinberg" <us15-IG//nw+yl+iQIjdd1DhZXWfrygkm6VTR@public.gmane.org>
To: Linux Kernel Mailing List <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: [PATCH]: Correctly locate RSDP in EBDA
ACPI spec. states that the location of the RSDP structure is found by searching
* The first 1 KB of the Extended BIOS Data Area (EBDA).
* The BIOS read-only memory space between 0E0000h and 0FFFFFh
The EBDA scan looks wrong. The patch below against 2.6.12 should correct this.
-Udo.
---
Calculate correct EBDA address for ACPI RSDP scan. The word at BIOS Data Area
40:0E is the segment address of the EBDA.
Signed-off-by: Udo A. Steinberg <us15-IG//nw+yl+iQIjdd1DhZXWfrygkm6VTR@public.gmane.org>
--- linux-2.6.12/arch/i386/kernel/acpi/boot.c.old 2005-07-20 17:28:32.000000000 +0200
+++ linux-2.6.12/arch/i386/kernel/acpi/boot.c 2005-07-20 17:31:15.000000000 +0200
@@ -648,7 +648,7 @@
* 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);
if (!rsdp_phys)
rsdp_phys = acpi_scan_rsdp (0xE0000, 0x20000);
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next reply other threads:[~2005-07-25 22:13 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-07-25 22:13 Andrew Morton [this message]
[not found] ` <20050725151313.730257bd.akpm-3NddpPZAyC0@public.gmane.org>
2005-07-26 9:53 ` Fw: [PATCH]: Correctly locate RSDP in EBDA Alan Cox
-- strict thread matches above, loose matches on Subject: below --
2005-07-25 22:19 Moore, Robert
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