From 39b68976ac653cfdc7f872a293e8b7928de2dcc6 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Mon, 25 Apr 2011 14:52:37 -0700 Subject: [PATCH] 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 Fix-proposed-by: Thomas Meyer Link: http://lkml.kernel.org/r/1303566747.12067.10.camel@localhost.localdomain --- arch/x86/boot/memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) 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 -- 2.39.5