Commit 39b68976 authored Apr 25, 2011 by H. Peter Anvin

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

parent 5dd12af0

arch/x86/boot/memory.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -91,7 +91,7 @@ static int detect_memory_e801(void)
	if (oreg.ax > 15*1024) {		if (oreg.ax > 15*1024) {
	return -1; /* Bogus! */		return -1; /* Bogus! */
	} else if (oreg.ax == 15*1024) {		} 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 {		} else {
	/*		/*
	* This ignores memory above 16MB if we have a memory		* This ignores memory above 16MB if we have a memory