Voodoo: Update VGA update frequency if required after timing change.

Added bool return value at Voodoo update() to indicate a timing change.
VGA core then calls set_update_timer() in vsync update mode.
Voodoo no longer reports mode and frequency if invalid.
This should fix issue #434.

bochs/iodev/display/banshee.cc

@@ -642,7 +642,7 @@ bool bx_banshee_c::chromakey_check(Bit32u color, Bit8u bpp)
   return pass;
 }
 
-void bx_banshee_c::update(void)
+bool bx_banshee_c::update(void)
 {
   Bit32u start;
   unsigned iHeight, iWidth, riHeight, riWidth;
@@ -689,7 +689,7 @@ void bx_banshee_c::update(void)
     if ((start + pitch * (riHeight - 1) + riWidth) > (v->fbi.mask + 1)) {
       BX_ERROR(("skip address wrap during update() (start = 0x%08x)", start));
       BX_UNLOCK(render_mutex);
-      return;
+      return false;
     }
     if (bx_gui->graphics_tile_info_common(&info)) {
       if (info.snapshot_mode) {
@@ -985,6 +985,7 @@ void bx_banshee_c::update(void)
   } else {
     bx_voodoo_base_c::update();
   }
+  return false;
 }
 
 Bit32u bx_banshee_c::get_retrace(bool hv)

bochs/iodev/display/vgacore.cc

@@ -2407,7 +2407,11 @@ void bx_vgacore_c::vga_timer_handler(void *this_ptr)
   bx_vgacore_c *vgadev = (bx_vgacore_c *) this_ptr;
 #if BX_SUPPORT_PCI
   if (vgadev->s.vga_override && (vgadev->s.nvgadev != NULL)) {
-    vgadev->s.nvgadev->update();
+    if (vgadev->s.nvgadev->update()) {
+      if (vgadev->update_mode_vsync) {
+        vgadev->set_update_timer(0);
+      }
+    }
   }
   else
 #endif

bochs/iodev/display/vgacore.h

@@ -75,7 +75,7 @@ class bx_nonvga_device_c : public bx_pci_device_c {
   virtual void redraw_area(unsigned x0, unsigned y0,
                            unsigned width, unsigned height) {}
   virtual void refresh_display(void *this_ptr, bool redraw) {}
-  virtual void update(void) {}
+  virtual bool update(void) {return false;}
   virtual Bit32u get_vtotal_usec(void) {return 0;}
 };
 #endif

bochs/iodev/display/voodoo.cc

@@ -553,7 +553,7 @@ void bx_voodoo_base_c::redraw_area(unsigned x0, unsigned y0, unsigned width,
   }
 }
 
-void bx_voodoo_base_c::update(void)
+bool bx_voodoo_base_c::update(void)
 {
   Bit32u start;
   unsigned iHeight, iWidth, riHeight, riWidth;
@@ -567,9 +567,11 @@ void bx_voodoo_base_c::update(void)
   bx_svga_tileinfo_t info;
 
   BX_LOCK(render_mutex);
+  bool retval = s.vdraw.vfreq_update;
+  s.vdraw.vfreq_update = false;
   if (!s.vdraw.gui_update_pending) {
     BX_UNLOCK(render_mutex);
-    return;
+    return retval;
   }
   BX_LOCK(fifo_mutex);
   if (s.model >= VOODOO_BANSHEE) {
@@ -601,7 +603,7 @@ void bx_voodoo_base_c::update(void)
   if ((start + pitch * (riHeight - 1) + riWidth) > (v->fbi.mask + 1)) {
     BX_ERROR(("skip address wrap during update() (start = 0x%08x)", start));
     BX_UNLOCK(render_mutex);
-    return;
+    return retval;
   }
   if (bx_gui->graphics_tile_info_common(&info)) {
     if (info.snapshot_mode) {
@@ -672,6 +674,7 @@ void bx_voodoo_base_c::update(void)
   }
   s.vdraw.gui_update_pending = 0;
   BX_UNLOCK(render_mutex);
+  return retval;
 }
 
 void bx_voodoo_base_c::reg_write(Bit32u reg, Bit32u value)
@@ -948,7 +951,7 @@ void bx_voodoo_1_2_c::mode_change_timer()
 bool bx_voodoo_1_2_c::update_timing(void)
 {
   int htotal, vtotal, hsync, vsync;
-  float hfreq;
+  float hfreq, old_vertfreq = v->vertfreq;
 
   if (!s.vdraw.clock_enabled || !s.vdraw.output_on)
     return 0;
@@ -970,6 +973,7 @@ bool bx_voodoo_1_2_c::update_timing(void)
     hfreq /= 2;
   }
   v->vertfreq = hfreq / (float)vtotal;
+  s.vdraw.vfreq_update = (v->vertfreq != old_vertfreq);
   s.vdraw.htotal_usec = (unsigned)(1000000.0 / hfreq);
   s.vdraw.vtotal_usec = (unsigned)(1000000.0 / v->vertfreq);
   s.vdraw.htime_to_pixel = (double)htotal / (1000000.0 / hfreq);
@@ -982,11 +986,12 @@ bool bx_voodoo_1_2_c::update_timing(void)
     bx_gui->dimension_update(v->fbi.width, v->fbi.height, 0, 0, 16);
     vertical_timer_handler(this);
   }
-  BX_INFO(("Voodoo output %dx%d@%uHz", v->fbi.width, v->fbi.height, (unsigned)v->vertfreq));
   v->fbi.swaps_pending = 0;
-  v->vtimer_running = 1;
-  if (v->vidclk != 0.0)
+  if (v->vidclk != 0.0) {
+    BX_INFO(("Voodoo output %dx%d@%uHz", v->fbi.width, v->fbi.height, (unsigned)v->vertfreq));
     bx_virt_timer.activate_timer(s.vertical_timer_id, (Bit32u)s.vdraw.vtotal_usec, 1);
+    v->vtimer_running = 1;
+  }
   return 1;
 }
 

bochs/iodev/display/voodoo.h

@@ -37,6 +37,7 @@ typedef struct {
     Bit64u vsync_usec;
     double htime_to_pixel;
     Bit64u frame_start;
+    bool vfreq_update;
     bool clock_enabled;
     bool output_on;
     bool override_on;
@@ -66,7 +67,7 @@ class bx_voodoo_base_c : public bx_nonvga_device_c {
   virtual void refresh_display(void *this_ptr, bool redraw);
   virtual void redraw_area(unsigned x0, unsigned y0,
                            unsigned width, unsigned height);
-  virtual void update(void);
+  virtual bool update(void);
   virtual bool update_timing(void) {return 0;}
   virtual Bit32u get_retrace(bool hv) {return 0;}
   virtual Bit32u get_vtotal_usec(void) {return 0;}
@@ -127,7 +128,7 @@ class bx_banshee_c : public bx_voodoo_base_c {
   virtual void register_state(void);
   virtual void after_restore_state(void);
 
-  virtual void   update(void);
+  virtual bool   update(void);
   virtual bool   update_timing(void);
   virtual Bit32u get_retrace(bool hv);