Append an MI_FLUSH to each batchbuffer for synchronization. Not really

ideal from a performance viewpoint and there are mechanisms to avoid this
in future.

src/mesa/drivers/dri/i915/i915_vtbl.c

@@ -360,14 +360,9 @@ static void i915_lost_hardware( struct intel_context *intel )
    i915->state.emitted = 0;
 }
 
-static void i915_emit_flush( struct intel_context *intel )
+static GLuint i915_flush_cmd( void )
 {
-   BATCH_LOCALS;
-
-   BEGIN_BATCH(2, 0);
-   OUT_BATCH( MI_FLUSH | FLUSH_MAP_CACHE | FLUSH_RENDER_CACHE ); 
-   OUT_BATCH( 0 );
-   ADVANCE_BATCH();
+   return MI_FLUSH | FLUSH_MAP_CACHE | FLUSH_RENDER_CACHE;
 }
 
 
@@ -382,6 +377,6 @@ void i915InitVtbl( struct i915_context *i915 )
    i915->intel.vtbl.render_start = i915_render_start;
    i915->intel.vtbl.set_draw_region = i915_set_draw_region;
    i915->intel.vtbl.update_texture_state = i915UpdateTextureState;
-   i915->intel.vtbl.emit_flush = i915_emit_flush;
+   i915->intel.vtbl.flush_cmd = i915_flush_cmd;
 }
 

src/mesa/drivers/dri/i915/intel_batchbuffer.c

@@ -161,7 +161,7 @@ static void do_flush_locked( struct intel_batchbuffer *batch,
       ptr[r->offset/4] = batch->offset[r->elem] + r->delta;
    }
 
-   if (0)
+   if (INTEL_DEBUG & DEBUG_DMA)
       intel_dump_batchbuffer( 0, ptr, used );
 
 
@@ -189,14 +189,17 @@ GLuint intel_batchbuffer_flush( struct intel_batchbuffer *batch )
    if (used == 0) 
       return batch->last_fence;
 
-   /* Add the MI_BATCH_BUFFER_END: 
+   /* Add the MI_BATCH_BUFFER_END.  Always add an MI_FLUSH - this is a
+    * performance drain that we would like to avoid.
     */
-   if (intel_batchbuffer_space(batch) & 4) {
-      ((int *)batch->ptr)[0] = MI_BATCH_BUFFER_END;
-      used += 4;
+   if (used & 4) {
+      ((int *)batch->ptr)[0] = intel->vtbl.flush_cmd();
+      ((int *)batch->ptr)[1] = 0;
+      ((int *)batch->ptr)[2] = MI_BATCH_BUFFER_END;
+      used += 12;
    }
    else {
-      ((int *)batch->ptr)[0] = 0;
+      ((int *)batch->ptr)[0] = intel->vtbl.flush_cmd();
       ((int *)batch->ptr)[1] = MI_BATCH_BUFFER_END;
       used += 8;
    }

src/mesa/drivers/dri/i915/intel_batchbuffer.h

@@ -7,6 +7,8 @@
 struct intel_context;
 
 #define BATCH_SZ 4096
+#define BATCH_RESERVED 16
+
 #define MAX_RELOCS 100
 
 #define INTEL_BATCH_NO_CLIPRECTS 0x1
@@ -72,7 +74,7 @@ GLboolean intel_batchbuffer_emit_reloc( struct intel_batchbuffer *batch,
 static inline GLuint 
 intel_batchbuffer_space( struct intel_batchbuffer *batch )
 {
-   return (BATCH_SZ - 8) - (batch->ptr - batch->map);
+   return (BATCH_SZ - BATCH_RESERVED) - (batch->ptr - batch->map);
 }
 
 

src/mesa/drivers/dri/i915/intel_blit.c

@@ -51,8 +51,7 @@ void intelCopyBuffer( const __DRIdrawablePrivate *dPriv )
 {
    struct intel_context *intel;
 
-   if (0)
-      fprintf(stderr, "%s\n", __FUNCTION__);
+   DBG(stderr, "%s\n", __FUNCTION__);
 
    assert(dPriv);
    assert(dPriv->driContextPriv);
@@ -188,12 +187,11 @@ void intelEmitCopyBlit( struct intel_context *intel,
    BATCH_LOCALS;
 
 
-   if (1)
-      _mesa_printf("%s src:buf(%d)/%d %d,%d dst:buf(%d)/%d %d,%d sz:%dx%d\n",
-		   __FUNCTION__,
-		   src_buffer, src_pitch, src_x, src_y,
-		   dst_buffer, dst_pitch, dst_x, dst_y,
-		   w,h);
+   DBG("%s src:buf(%d)/%d %d,%d dst:buf(%d)/%d %d,%d sz:%dx%d\n",
+       __FUNCTION__,
+       src_buffer, src_pitch, src_x, src_y,
+       dst_buffer, dst_pitch, dst_x, dst_y,
+       w,h);
 
    src_pitch *= cpp;
    dst_pitch *= cpp;

src/mesa/drivers/dri/i915/intel_context.h

@@ -121,7 +121,8 @@ struct intel_context
       void (*set_draw_region)( struct intel_context *intel, 
 			       struct intel_region *draw_region,
 			       struct intel_region *depth_region );
-      void (*emit_flush)( struct intel_context *intel );
+
+      GLuint (*flush_cmd)( void );
 
       void (*reduced_primitive_state)( struct intel_context *intel, GLenum rprim );
 

src/mesa/drivers/dri/i915/intel_ioctl.c

@@ -123,7 +123,7 @@ void intel_batch_ioctl( struct intel_context *intel,
    batch.DR4 = ((((GLuint)intel->drawX) & 0xffff) | 
 		(((GLuint)intel->drawY) << 16));
       
-   if (0)
+   if (INTEL_DEBUG & DEBUG_DMA)
       fprintf(stderr, "%s: 0x%x..0x%x DR4: %x cliprects: %d\n",
 	      __FUNCTION__, 
 	      batch.start,