Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762200AbXIZW14 (ORCPT ); Wed, 26 Sep 2007 18:27:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754678AbXIZW1t (ORCPT ); Wed, 26 Sep 2007 18:27:49 -0400 Received: from terminus.zytor.com ([198.137.202.10]:44902 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751888AbXIZW1s (ORCPT ); Wed, 26 Sep 2007 18:27:48 -0400 Date: Wed, 26 Sep 2007 15:27:20 -0700 Message-Id: <200709262227.l8QMRKFE000784@tazenda.hos.anvin.org> From: "H. Peter Anvin" To: Linus Torvalds Cc: Linux Kernel Mailing List , Jordan Crouse , Joerg Pommnitz Subject: [GIT PULL] Workaround for broken Geode E820 BIOS Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2733 Lines: 100 Hi Linus, Please pull: git://git.kernel.org/pub/scm/linux/kernel/git/hpa/linux-2.6-x86setup.git for-linus H. Peter Anvin (1): [x86 setup] Handle case of improperly terminated E820 chain arch/i386/boot/memory.c | 30 +++++++++++++++++++++++------- 1 files changed, 23 insertions(+), 7 deletions(-) [Log messages and full diffs follow] commit 2efa33f81ef56e7700c09a3d8a881c96692149e5 Author: H. Peter Anvin Date: Wed Sep 26 14:11:43 2007 -0700 [x86 setup] Handle case of improperly terminated E820 chain At least one system (a Geode system with a Digital Logic BIOS) has been found which suddenly stops reporting the SMAP signature when reading the E820 memory chain. We can't know what, exactly, broke in the BIOS, so if we detect this situation, declare the E820 data unusable and fall back to E801. Also, revert to original behavior of always probing all memory methods; that way all the memory information is available to the kernel. Signed-off-by: H. Peter Anvin Cc: Jordan Crouse Cc: Joerg Pommnitz diff --git a/arch/i386/boot/memory.c b/arch/i386/boot/memory.c index 1a2e62d..bccaa1c 100644 --- a/arch/i386/boot/memory.c +++ b/arch/i386/boot/memory.c @@ -20,6 +20,7 @@ static int detect_memory_e820(void) { + int count = 0; u32 next = 0; u32 size, id; u8 err; @@ -33,14 +34,24 @@ static int detect_memory_e820(void) "=m" (*desc) : "D" (desc), "a" (0xe820)); - if (err || id != SMAP) + /* Some BIOSes stop returning SMAP in the middle of + the search loop. We don't know exactly how the BIOS + screwed up the map at that point, we might have a + partial map, the full map, or complete garbage, so + just return failure. */ + if (id != SMAP) { + count = 0; break; + } - boot_params.e820_entries++; + if (err) + break; + + count++; desc++; - } while (next && boot_params.e820_entries < E820MAX); + } while (next && count < E820MAX); - return boot_params.e820_entries; + return boot_params.e820_entries = count; } static int detect_memory_e801(void) @@ -89,11 +100,16 @@ static int detect_memory_88(void) int detect_memory(void) { + int err = -1; + if (detect_memory_e820() > 0) - return 0; + err = 0; if (!detect_memory_e801()) - return 0; + err = 0; + + if (!detect_memory_88()) + err = 0; - return detect_memory_88(); + return err; } - 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/