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Commit 112522f6 authored by Chris Wilson's avatar Chris Wilson Committed by Daniel Vetter
Browse files

drm/i915: put context upon switching 



In order to be notified of when the context and all of its associated
objects is idle (for if the context maps to a ppgtt) we need a callback
from the retire handler. We can arrange this by using the kref_get/put
of the context for request tracking and by inserting a request to
demarque the switch away from the old context.

[Ben: fixed minor error to patch compile, AND s/last_context/from/]
Signed-off-by: default avatarBen Widawsky <ben@bwidawsk.net>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 21a8e6a4

drivers/gpu/drm/i915/i915_gem_context.c

+24 −13
Original line number Diff line number Diff line
@@ -361,13 +361,13 @@ mi_set_context(struct intel_ring_buffer *ring, 
static int do_switch(struct i915_hw_context *to)

{

	struct intel_ring_buffer *ring = to->ring;

	struct drm_i915_gem_object *from_obj = ring->last_context_obj;

	struct i915_hw_context *from = ring->last_context;

	u32 hw_flags = 0;

	int ret;



	BUG_ON(from_obj != NULL && from_obj->pin_count == 0);

	BUG_ON(from != NULL && from->obj != NULL && from->obj->pin_count == 0);



	if (from_obj == to->obj)

	if (from == to)

		return 0;



	ret = i915_gem_object_pin(to->obj, CONTEXT_ALIGN, false, false);
@@ -390,7 +390,7 @@ static int do_switch(struct i915_hw_context *to) 


	if (!to->is_initialized || is_default_context(to))

		hw_flags |= MI_RESTORE_INHIBIT;

	else if (WARN_ON_ONCE(from_obj == to->obj)) /* not yet expected */

	else if (WARN_ON_ONCE(from == to)) /* not yet expected */

		hw_flags |= MI_FORCE_RESTORE;



	ret = mi_set_context(ring, to, hw_flags);
@@ -405,9 +405,9 @@ static int do_switch(struct i915_hw_context *to) 
	 * is a bit suboptimal because the retiring can occur simply after the

	 * MI_SET_CONTEXT instead of when the next seqno has completed.

	 */

	if (from_obj != NULL) {

		from_obj->base.read_domains = I915_GEM_DOMAIN_INSTRUCTION;

		i915_gem_object_move_to_active(from_obj, ring);

	if (from != NULL) {

		from->obj->base.read_domains = I915_GEM_DOMAIN_INSTRUCTION;

		i915_gem_object_move_to_active(from->obj, ring);

		/* As long as MI_SET_CONTEXT is serializing, ie. it flushes the

		 * whole damn pipeline, we don't need to explicitly mark the

		 * object dirty. The only exception is that the context must be
@@ -415,15 +415,26 @@ static int do_switch(struct i915_hw_context *to) 
		 * able to defer doing this until we know the object would be

		 * swapped, but there is no way to do that yet.

		 */

		from_obj->dirty = 1;

		BUG_ON(from_obj->ring != ring);

		i915_gem_object_unpin(from_obj);

		from->obj->dirty = 1;

		BUG_ON(from->obj->ring != ring);



		drm_gem_object_unreference(&from_obj->base);

		ret = i915_add_request(ring, NULL, NULL);

		if (ret) {

			/* Too late, we've already scheduled a context switch.

			 * Try to undo the change so that the hw state is

			 * consistent with out tracking. In case of emergency,

			 * scream.

			 */

			WARN_ON(mi_set_context(ring, from, MI_RESTORE_INHIBIT));

			return ret;

		}



		i915_gem_object_unpin(from->obj);

		i915_gem_context_unreference(from);

	}



	drm_gem_object_reference(&to->obj->base);

	ring->last_context_obj = to->obj;

	i915_gem_context_reference(to);

	ring->last_context = to;

	to->is_initialized = true;



	return 0;

drivers/gpu/drm/i915/intel_ringbuffer.h

+1 −1
Original line number Diff line number Diff line
@@ -135,7 +135,7 @@ struct intel_ring_buffer { 
	 */

	bool itlb_before_ctx_switch;

	struct i915_hw_context *default_context;

	struct drm_i915_gem_object *last_context_obj;

	struct i915_hw_context *last_context;



	void *private;

};