From 43c419ecdb94b37887dce7c7031e573a08304e6e Mon Sep 17 00:00:00 2001
From: AITUS95 <48457684+AITUS95@users.noreply.github.com>
Date: Fri, 9 Jan 2026 13:00:11 +0100
Subject: [PATCH] Enhance VGA pass-through handling in vid_voodoo.c

Added logic to handle VGA pass-through state changes and mark lines dirty for refresh.
---
 src/video/vid_voodoo.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/video/vid_voodoo.c b/src/video/vid_voodoo.c
index 960b913a9..6920ece5c 100644
--- a/src/video/vid_voodoo.c
+++ b/src/video/vid_voodoo.c
@@ -516,6 +516,7 @@ voodoo_writel(uint32_t addr, uint32_t val, void *priv)
                 break;
             case SST_fbiInit0:
                 if (voodoo->initEnable & 0x01) {
+                    int old_vga_pass = voodoo->fbiInit0 & FBIINIT0_VGA_PASS;
                     voodoo->fbiInit0 = val;
                     thread_wait_mutex(voodoo->force_blit_mutex);
                     voodoo->can_blit = (voodoo->fbiInit0 & FBIINIT0_VGA_PASS) ? 1 : 0;
@@ -523,6 +524,10 @@ voodoo_writel(uint32_t addr, uint32_t val, void *priv)
                         voodoo->force_blit_count = 0;
                     thread_release_mutex(voodoo->force_blit_mutex);
 
+                    /* When VGA pass-through becomes active, mark all lines dirty to force full refresh */
+                    if (!old_vga_pass && (val & FBIINIT0_VGA_PASS))
+                        memset(voodoo->dirty_line, 1, sizeof(voodoo->dirty_line));
+
                     if (voodoo->set->nr_cards == 2)
                         svga_set_override(voodoo->svga, (voodoo->set->voodoos[0]->fbiInit0 | voodoo->set->voodoos[1]->fbiInit0) & 1);
                     else