From: H. Peter Anvin Date: Mon, 25 Apr 2011 21:52:37 +0000 (-0700) Subject: x86, setup: When probing memory with e801, use ax/bx as a pair X-Git-Tag: firefly_0821_release~7613^2~1521^2~2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=39b68976ac653cfdc7f872a293e8b7928de2dcc6;p=firefly-linux-kernel-4.4.55.git 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 --- 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