drm/i915: Clarify the semantics of tiling_changed

Rename obj->tiling_changed to obj->fence_dirty so that it is clear that
it flags when the parameters for an active fence (including the
no-fence) register are changed.

Also, do not set this flag when the object does not have a fence
register allocated currently and the gpu does not depend upon the
unfence. This case works exactly like when a tiled object lost its
fence and hence does not need additional handling for the tiling
change in the code.

v2: Use fence_dirty to better express what the flag tracks and add a few
more details to the comments to serve as a reminder of how the GPU also
uses the unfenced register slot.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: Add some bikeshed to the commit message about the stricter
use of fence_dirty.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 9e9ea759e496..38490cdf2d9f 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -66,7 +66,7 @@ static inline void i915_gem_object_fence_lost(struct drm_i915_gem_object *obj)
         /* As we do not have an associated fence register, we will force
          * a tiling change if we ever need to acquire one.
          */
-        obj->tiling_changed = false;
+        obj->fence_dirty = false;
         obj->fence_reg = I915_FENCE_REG_NONE;
 }
 
@@ -2459,7 +2459,7 @@ i915_gem_object_get_fence(struct drm_i915_gem_object *obj)
         /* Have we updated the tiling parameters upon the object and so
          * will need to serialise the write to the associated fence register?
          */
-        if (obj->tiling_changed) {
+        if (obj->fence_dirty) {
                 ret = i915_gem_object_flush_fence(obj);
                 if (ret)
                         return ret;
@@ -2468,7 +2468,7 @@ i915_gem_object_get_fence(struct drm_i915_gem_object *obj)
         /* Just update our place in the LRU if our fence is getting reused. */
         if (obj->fence_reg != I915_FENCE_REG_NONE) {
                 reg = &dev_priv->fence_regs[obj->fence_reg];
-                if (!obj->tiling_changed) {
+                if (!obj->fence_dirty) {
                         list_move_tail(&reg->lru_list,
                                        &dev_priv->mm.fence_list);
                         return 0;
@@ -2491,7 +2491,7 @@ i915_gem_object_get_fence(struct drm_i915_gem_object *obj)
                 return 0;
 
         i915_gem_object_update_fence(obj, reg, enable);
-        obj->tiling_changed = false;
+        obj->fence_dirty = false;
 
         return 0;
 }