drm/i915: Only enforce fence limits inside the GTT.

So long as we adhere to the fence registers rules for alignment and no
overlaps (including with unfenced accesses to linear memory) and account
for the tiled access in our size allocation, we do not have to allocate
the full fenced region for the object. This allows us to fight the bloat
tiling imposed on pre-i965 chipsets and frees up RAM for real use. [Inside
the GTT we still suffer the additional alignment constraints, so it doesn't
magic allow us to render larger scenes without stalls -- we need the
expanded GTT and fence pipelining to overcome those...]

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -130,7 +130,8 @@ describe_obj(struct seq_file *m, struct drm_i915_gem_object *obj)
 	if (obj->fence_reg != I915_FENCE_REG_NONE)
 		seq_printf(m, " (fence: %d)", obj->fence_reg);
 	if (obj->gtt_space != NULL)
-		seq_printf(m, " (gtt_offset: %08x)", obj->gtt_offset);
+		seq_printf(m, " (gtt offset: %08x, size: %08x)",
+			   obj->gtt_offset, (unsigned int)obj->gtt_space->size);
 	if (obj->pin_mappable || obj->fault_mappable)
 		seq_printf(m, " (mappable)");
 	if (obj->ring != NULL)

drivers/gpu/drm/i915/i915_dma.c

@@ -770,6 +770,9 @@ static int i915_getparam(struct drm_device *dev, void *data,
 	case I915_PARAM_HAS_BLT:
 		value = HAS_BLT(dev);
 		break;
+	case I915_PARAM_HAS_RELAXED_FENCING:
+		value = 1;
+		break;
 	default:
 		DRM_DEBUG_DRIVER("Unknown parameter %d\n",
 				 param->param);

drivers/gpu/drm/i915/i915_drv.h

@@ -746,6 +746,8 @@ struct drm_i915_gem_object {
 	 * Advice: are the backing pages purgeable?
 	 */
 	unsigned int madv : 2;
+	unsigned int fenceable : 1;
+	unsigned int mappable : 1;
 
 	/**
 	 * Current tiling mode for the object.
@@ -1005,7 +1007,7 @@ struct drm_gem_object * i915_gem_alloc_object(struct drm_device *dev,
 					      size_t size);
 void i915_gem_free_object(struct drm_gem_object *obj);
 int i915_gem_object_pin(struct drm_gem_object *obj, uint32_t alignment,
-			bool mappable);
+			bool mappable, bool need_fence);
 void i915_gem_object_unpin(struct drm_gem_object *obj);
 int i915_gem_object_unbind(struct drm_gem_object *obj);
 void i915_gem_release_mmap(struct drm_gem_object *obj);
@@ -1068,10 +1070,6 @@ int i915_gem_evict_inactive(struct drm_device *dev);
 void i915_gem_detect_bit_6_swizzle(struct drm_device *dev);
 void i915_gem_object_do_bit_17_swizzle(struct drm_gem_object *obj);
 void i915_gem_object_save_bit_17_swizzle(struct drm_gem_object *obj);
-bool i915_tiling_ok(struct drm_device *dev, int stride, int size,
-		    int tiling_mode);
-bool i915_gem_object_fence_offset_ok(struct drm_gem_object *obj,
-				     int tiling_mode);
 
 /* i915_gem_debug.c */
 void i915_gem_dump_object(struct drm_gem_object *obj, int len,