From aad5eb3e23b71b17148a2bfadf1512f8bd4697ba Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Strohh=C3=A4cker?=
 <c2woody@users.sourceforge.net>
Date: Mon, 8 Jan 2007 21:58:37 +0000
Subject: [PATCH] fully clear display start on graphics mode switches (duke3d
 vesa exit)

Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@2738
---
 src/ints/int10_modes.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/ints/int10_modes.cpp b/src/ints/int10_modes.cpp
index 8f4db1b7..24066be4 100644
--- a/src/ints/int10_modes.cpp
+++ b/src/ints/int10_modes.cpp
@@ -681,6 +681,9 @@ bool INT10_SetVideoMode(Bitu mode) {
 	/* This register actually has more bits but only use the extended offset ones */
 	IO_Write(crtc_base,0x51);
 	IO_Write(crtc_base + 1,(offset & 0x300) >> 4);
+	/* Clear remaining bits of the display start */
+	IO_Write(crtc_base,0x69);
+	IO_Write(crtc_base + 1,0);
 	/* Extended Vertical Overflow */
 	IO_Write(crtc_base,0x5e);IO_Write(crtc_base+1,ver_overflow);