From ca53dd028075fcdbb46936cd8f04ff4e51f2e9e4 Mon Sep 17 00:00:00 2001
From: TC1995 <mariogplayer90@gmail.com>
Date: Mon, 19 Jun 2017 22:32:16 +0200
Subject: [PATCH] S3 Trio/Vision changes (again x2): Trio32/64 with on-chip
 ramdac instead of SDAC. FIFO Empty/Full status from 9ae8/9ae9 no longer
 slowing down OS/2 when native drivers are installed.

---
 src/VIDEO/vid_s3.c | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/src/VIDEO/vid_s3.c b/src/VIDEO/vid_s3.c
index 6cc18d7e9..3401ecd03 100644
--- a/src/VIDEO/vid_s3.c
+++ b/src/VIDEO/vid_s3.c
@@ -86,6 +86,7 @@ typedef struct s3_t
         int card;
 
         uint32_t vram_mask;
+		uint8_t status_9ae8;
         
         float (*getclock)(int clock, void *p);
         void *getclock_p;
@@ -792,7 +793,12 @@ void s3_out(uint16_t addr, uint8_t val, void *p)
                 break;
                 
                 case 0x3C6: case 0x3C7: case 0x3C8: case 0x3C9:
-                sdac_ramdac_out(addr, val, &s3->ramdac, svga);
+                if (s3->chip < S3_TRIO32)
+				{
+					sdac_ramdac_out(addr, val, &s3->ramdac, svga);
+					return;
+				}
+				svga_out(addr, val, svga);
                 return;
 
                 case 0x3D4:
@@ -930,7 +936,10 @@ uint8_t s3_in(uint16_t addr, void *p)
                 break;
                 
                 case 0x3c6: case 0x3c7: case 0x3c8: case 0x3c9:
-                return sdac_ramdac_in(addr, &s3->ramdac, svga);
+				if (s3->chip < S3_TRIO32)	
+					return sdac_ramdac_in(addr, &s3->ramdac, svga);
+				
+				return svga_in(addr, svga);
 
                 case 0x3d4:
                 return svga->crtcreg;
@@ -1214,7 +1223,7 @@ uint8_t s3_accel_in(uint16_t port, void *p)
                 if (!FIFO_EMPTY)
                         temp |= 0x02; /*Hardware busy*/
                 else
-                        temp |= 0x04; /*FIFO empty*/
+                        temp |= s3->status_9ae8; /*FIFO empty*/
                 if (FIFO_FULL)
                         temp |= 0xf8; /*FIFO full*/
                 return temp;
@@ -1604,6 +1613,14 @@ void s3_accel_start(int count, int cpu_input, uint32_t mix_dat, uint32_t cpu_dat
                 frgd_mix = (s3->accel.frgd_mix >> 5) & 3;
                 bkgd_mix = (s3->accel.bkgd_mix >> 5) & 3;
                 
+				s3->status_9ae8 = 4; /*To avoid the spam from OS/2's drivers*/
+
+				if ((s3->accel.cmd & 0x100) && !cpu_input)
+				{
+					s3->status_9ae8 = 2; /*To avoid the spam from OS/2's drivers*/
+					return; /*Wait for data from CPU*/
+				}				
+				
                 while (count-- && s3->accel.sy >= 0)
                 {
                         if (s3->accel.cx >= clip_l && s3->accel.cx <= clip_r &&
@@ -1688,7 +1705,8 @@ void s3_accel_start(int count, int cpu_input, uint32_t mix_dat, uint32_t cpu_dat
                 bkgd_mix = (s3->accel.bkgd_mix >> 5) & 3;
                 
                 if (!cpu_input && frgd_mix == 3 && !vram_mask && !compare_mode &&
-                    (s3->accel.cmd & 0xa0) == 0xa0 && (s3->accel.frgd_mix & 0xf) == 7) 
+                    (s3->accel.cmd & 0xa0) == 0xa0 && (s3->accel.frgd_mix & 0xf) == 7 &&
+					(s3->accel.bkgd_mix & 0xf) == 7)
                 {
                         while (1)
                         {