drm/i915: BUG() if fences are used on unsupported platform

Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_gem.c

@@ -2649,7 +2649,7 @@ static void i915_gem_write_fence(struct drm_device *dev, int reg,
 	case 4: i965_write_fence_reg(dev, reg, obj); break;
 	case 3: i915_write_fence_reg(dev, reg, obj); break;
 	case 2: i830_write_fence_reg(dev, reg, obj); break;
-	default: break;
+	default: BUG();
 	}
 }
 

drivers/gpu/drm/i915/i915_irq.c

@@ -1106,6 +1106,8 @@ static void i915_gem_record_fences(struct drm_device *dev,
 			error->fence[i] = I915_READ(FENCE_REG_830_0 + (i * 4));
 		break;
 
+	default:
+		BUG();
 	}
 }