[PATCH] reset qxl to vga mode

[qi zhou <atmgnd@xxxxxxxxxxx>]

from https://github.com/qemu/qemu/commit/ed71c09ffd6fbd01c2a487d47291ae57b08671ea
QXL device rev 5+ requires explicit reset to switch to VGA mode.
in windows, if bsod happens, windows cannot switch qxl gpu from qxl mode to vga mode. It is important to reset to vga mode after windows system bsod, so the blue screen can show

below is the patch:


>From 9c4ba40a02d4fa517b069e8a795c5b570091c928 Mon Sep 17 00:00:00 2001
From: Qi Zhou <atmgnd@xxxxxxxxxxx>
Date: Tue, 14 Feb 2023 11:31:08 +0800
Subject: [PATCH] reset qxl to vga mode

in windows guest, if we trigger a bluescreen, windows will reset gpu to vga
mode, otherwise the bluescreen will not shown

Signed-off-by: Qi Zhou <atmgnd@xxxxxxxxxxx>
---
 qxldod/QxlDod.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/qxldod/QxlDod.cpp b/qxldod/QxlDod.cpp
index f498115..25b9af6 100755
--- a/qxldod/QxlDod.cpp
+++ b/qxldod/QxlDod.cpp
@@ -3869,7 +3869,7 @@ void QxlDevice::ResetDevice(void)
 {
     DbgPrint(TRACE_LEVEL_VERBOSE, ("---> %s\n", __FUNCTION__));
     m_RamHdr->int_mask = ~0;
-    WRITE_PORT_UCHAR(m_IoBase + QXL_IO_MEMSLOT_ADD, 0);
+    WRITE_PORT_UCHAR(m_IoBase + QXL_IO_RESET, 0);
     DbgPrint(TRACE_LEVEL_VERBOSE, ("<--- %s\n", __FUNCTION__));
 }
 
-- 
2.30.0.windows.1