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Commit 5d82e3e6 authored by Chris Wilson's avatar Chris Wilson Committed by Daniel Vetter
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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: default avatarChris Wilson <chris@chris-wilson.co.uk>
[danvet: Add some bikeshed to the commit message about the stricter
use of fence_dirty.]
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 38de45c5

drivers/gpu/drm/i915/i915_drv.h

+8 −1
Original line number Diff line number Diff line
@@ -869,7 +869,14 @@ struct drm_i915_gem_object { 
	 * Current tiling mode for the object.

	 */

	unsigned int tiling_mode:2;

	unsigned int tiling_changed:1;

	/**

	 * Whether the tiling parameters for the currently associated fence

	 * register have changed. Note that for the purposes of tracking

	 * tiling changes we also treat the unfenced register, the register

	 * slot that the object occupies whilst it executes a fenced

	 * command (such as BLT on gen2/3), as a "fence".

	 */

	unsigned int fence_dirty:1;



	/** How many users have pinned this object in GTT space. The following

	 * users can each hold at most one reference: pwrite/pread, pin_ioctl

drivers/gpu/drm/i915/i915_gem.c

+4 −4
Original line number Diff line number Diff line
@@ -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;

}

drivers/gpu/drm/i915/i915_gem_tiling.c

+9 −1
Original line number Diff line number Diff line
@@ -355,6 +355,11 @@ i915_gem_set_tiling(struct drm_device *dev, void *data, 
		 * no longer meets the alignment restrictions for its new

		 * tiling mode. Otherwise we can just leave it alone, but

		 * need to ensure that any fence register is cleared.

		 *

		 * After updating the tiling parameters, we then flag whether

		 * we need to update an associated fence register. Note this

		 * has to also include the unfenced register the GPU uses

		 * whilst executing a fenced command for an untiled object.

		 */

		i915_gem_release_mmap(obj);
@@ -374,7 +379,10 @@ i915_gem_set_tiling(struct drm_device *dev, void *data, 
		}



		if (ret == 0) {

			obj->tiling_changed = true;

			obj->fence_dirty =

				obj->fenced_gpu_access ||

				obj->fence_reg != I915_FENCE_REG_NONE;



			obj->tiling_mode = args->tiling_mode;

			obj->stride = args->stride;

		}