From 45f28b12bd71042d3fb6f9efae75f84d5b682b6a Mon Sep 17 00:00:00 2001
From: ripsaw8080 <ripsaw8080@users.sourceforge.net>
Date: Mon, 4 Feb 2019 15:27:26 +0000
Subject: [PATCH] Only standard 3-byte mouse data packets are supported, so
 return an error for other packet sizes. MS Mouse driver versions 9.X and
 later use 1-byte packets for some obscure reason, and now they won't load
 instead of messing up.

Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@4191
---
 src/ints/bios.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/ints/bios.cpp b/src/ints/bios.cpp
index ef906283..dfeb0a15 100644
--- a/src/ints/bios.cpp
+++ b/src/ints/bios.cpp
@@ -905,6 +905,12 @@ static Bitu INT15_Handler(void) {
 			reg_bx=0x00aa;	// mouse
 			// fall through
 		case 0x05:		// initialize
+			if ((reg_al==0x05) && (reg_bh!=0x03)) {
+				// non-standard data packet sizes not supported
+				CALLBACK_SCF(true);
+				reg_ah=2;
+				break;
+			}
 			Mouse_SetPS2State(false);
 			CALLBACK_SCF(false);
 			reg_ah=0;