From ee32db0f9c0ff7549cb4a65c0300d8163b8049fb Mon Sep 17 00:00:00 2001
From: yz70s <yz70s@users.noreply.github.com>
Date: Mon, 30 Aug 2021 19:58:53 +0200
Subject: [PATCH] 8042kbdc.cpp: mouse reset answers at least one byte if mouse
 disabled. Makes nforcepc bios happy.

---
 src/devices/machine/8042kbdc.cpp | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/devices/machine/8042kbdc.cpp b/src/devices/machine/8042kbdc.cpp
index a2e29d90c4f..c86a44a1f0a 100644
--- a/src/devices/machine/8042kbdc.cpp
+++ b/src/devices/machine/8042kbdc.cpp
@@ -407,9 +407,17 @@ void kbdc8042_device::data_w(offs_t offset, uint8_t data)
 					m_mouse.from_transmit = 0;
 					m_mouse.to_transmit = 0;
 					m_mouse.reporting = false;
-					mouse_enqueue(0xfa);
-					mouse_enqueue(0xaa);
-					mouse_enqueue(0x00);
+					if (m_mouse.on)
+					{
+						mouse_enqueue(0xfa);
+						mouse_enqueue(0xaa);
+						mouse_enqueue(0x00);
+					}
+					else
+					{
+						m_mouse.received = 1;
+						m_data = 0xfa;
+					}
 					break;
 				case 0xf6:
 					mouse_enqueue(0xfa);