From: Andrey Borzenkov <arvidjaar@mail.ru>
Date: Sat, 25 Mar 2006 11:07:07 +0000 (-0800)
Subject: [PATCH] Fix EDD to properly ignore signature of non-existing drives
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=2c3ca07d2f691a463b715c83122c87f57c2a7b7c;p=deliverable%2Flinux.git

[PATCH] Fix EDD to properly ignore signature of non-existing drives

Some BIOSes do not always set CF on error before return from int13.  The
patch adds additional check for status being zero (AH == 0).

Signed-off-by: Andrey Borzenkov <arvidjaar@mail.ru>
Cc: Matt Domsch <Matt_Domsch@dell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/arch/i386/boot/edd.S b/arch/i386/boot/edd.S
index d8d69f2b911d..4b84ea216f2b 100644
--- a/arch/i386/boot/edd.S
+++ b/arch/i386/boot/edd.S
@@ -76,6 +76,8 @@ edd_mbr_sig_read:
 	popw	%es
 	popw	%bx
 	jc	edd_mbr_sig_done		# on failure, we're done.
+	cmpb	$0, %ah		# some BIOSes do not set CF
+	jne	edd_mbr_sig_done		# on failure, we're done.
 	movl	(EDDBUF+EDD_MBR_SIG_OFFSET), %eax # read sig out of the MBR
 	movl	%eax, (%bx)			# store success
 	incb	(EDD_MBR_SIG_NR_BUF)		# note that we stored something