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authorH. Peter Anvin <hpa@linux.intel.com>2011-04-25 14:52:37 -0700
committerH. Peter Anvin <hpa@linux.intel.com>2011-04-25 14:52:37 -0700
commit39b68976ac653cfdc7f872a293e8b7928de2dcc6 (patch)
treecaf1d25a448fdf56878de7fb700b26655676ca0d /arch/x86/boot
parent5dd12af05ca6b7d052c06a9ca4ff755fdfa25ae4 (diff)
downloadlinux-39b68976ac653cfdc7f872a293e8b7928de2dcc6.tar.gz
x86, setup: When probing memory with e801, use ax/bx as a pair
When we use BIOS function e801 to probe memory, we should use ax/bx
(or cx/dx) as a pair, not mix and match.  This was a typo during the
translation from assembly code, and breaks at least one set of
machines in the field (which return cx = dx = 0).

Reported-and-tested-by: Chris Samuel <chris@csamuel.org>
Fix-proposed-by: Thomas Meyer <thomas@m3y3r.de>
Link: http://lkml.kernel.org/r/1303566747.12067.10.camel@localhost.localdomain
Diffstat (limited to 'arch/x86/boot')
-rw-r--r--arch/x86/boot/memory.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/boot/memory.c b/arch/x86/boot/memory.c
index cae3feb1035e..db75d07c3645 100644
--- a/arch/x86/boot/memory.c
+++ b/arch/x86/boot/memory.c
@@ -91,7 +91,7 @@ static int detect_memory_e801(void)
 	if (oreg.ax > 15*1024) {
 		return -1;	/* Bogus! */
 	} else if (oreg.ax == 15*1024) {
-		boot_params.alt_mem_k = (oreg.dx << 6) + oreg.ax;
+		boot_params.alt_mem_k = (oreg.bx << 6) + oreg.ax;
 	} else {
 		/*
 		 * This ignores memory above 16MB if we have a memory