From 97b24a0865407b0e3c49226a0b086eee23042ec7 Mon Sep 17 00:00:00 2001
From: Toni Wilen <twilen@winuae.net>
Date: Sun, 4 May 2025 13:11:22 +0300
Subject: [PATCH] Keep FB only mode unless VGA planar mode is selected (4 or 16
 colors).

---
 pcem/vid_cl5429.cpp |  3 ++-
 pcem/vid_svga.cpp   | 13 +++++++++++++
 pcem/vid_svga.h     |  2 +-
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/pcem/vid_cl5429.cpp b/pcem/vid_cl5429.cpp
index 40d93b6d..f0fff68b 100644
--- a/pcem/vid_cl5429.cpp
+++ b/pcem/vid_cl5429.cpp
@@ -2897,7 +2897,8 @@ static void *cl_init(int type, char *fn, int pci_card, uint32_t force_vram_size)
                 gd5429->pci_regs[0x33] = 0x00;
         }
 
-        gd5429->svga.fb_only = 0;
+        gd5429->svga.fb_only = -1;
+        gd5429->svga.fb_auto = 1;
         
         return gd5429;
 }
diff --git a/pcem/vid_svga.cpp b/pcem/vid_svga.cpp
index 478eaa65..51d3715c 100644
--- a/pcem/vid_svga.cpp
+++ b/pcem/vid_svga.cpp
@@ -342,6 +342,10 @@ void svga_recalctimings(svga_t *svga)
         double _dispontime, _dispofftime, disptime;
         int text = 0;
 
+        if (svga->fb_auto == 1) {
+            svga->fb_only = -1;
+        }
+
         svga->vtotal = svga->crtc[6];
         svga->dispend = svga->crtc[0x12];
         svga->vsyncstart = svga->crtc[0x10];
@@ -416,6 +420,9 @@ void svga_recalctimings(svga_t *svga)
             }
             svga->hdisp_old = svga->hdisp;
             text = 1;
+            if (svga->fb_auto) {
+                svga->fb_only = 0;
+            }
         }
         else
         {
@@ -429,12 +436,18 @@ void svga_recalctimings(svga_t *svga)
                     svga->render = svga_render_4bpp_lowres;
                 else
                     svga->render = svga_render_4bpp_highres;
+                if (svga->fb_auto) {
+                    svga->fb_only = 0;
+                }
                 break;
             case 0x20: /*4 colours*/
                 if (svga->seqregs[1] & 8) /*Low res (320)*/
                     svga->render = svga_render_2bpp_lowres;
                 else
                     svga->render = svga_render_2bpp_highres;
+                if (svga->fb_auto) {
+                    svga->fb_only = 0;
+                }
                 break;
             case 0x40: case 0x60: /*256+ colours*/
                 switch (svga->bpp)
diff --git a/pcem/vid_svga.h b/pcem/vid_svga.h
index 5ca4a6b9..6f4364ca 100644
--- a/pcem/vid_svga.h
+++ b/pcem/vid_svga.h
@@ -55,7 +55,7 @@ typedef struct svga_t
         
         uint8_t plane_mask;
         
-        int fb_only;
+        int fb_only, fb_auto;
         
         int fast;
         uint8_t colourcompare, colournocare;
-- 
2.47.3