[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 d8d69f2..4b84ea2 100644
--- a/arch/i386/boot/edd.S
+++ b/arch/i386/boot/edd.S
@@ -76,6 +76,8 @@
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