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Commit 9a3b5304 authored by Chris Wilson's avatar Chris Wilson Committed by Daniel Vetter
Browse files

drm/i915: Cleanup context switching through do_switch() 



When bug hunting, I found the interface to do_switch() overly
complicated and I believe festered the earlier bug. This aims to make
the code a little clearer.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarBen Widawsky <ben@bwidawsk.net>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 54d63ca6

drivers/gpu/drm/i915/i915_gem_context.c

+26 −31
Original line number Diff line number Diff line
@@ -97,8 +97,7 @@ 


static struct i915_hw_context *

i915_gem_context_get(struct drm_i915_file_private *file_priv, u32 id);

static int do_switch(struct drm_i915_gem_object *from_obj,

		     struct i915_hw_context *to, u32 seqno);

static int do_switch(struct i915_hw_context *to);



static int get_context_size(struct drm_device *dev)

{
@@ -220,19 +219,20 @@ static int create_default_context(struct drm_i915_private *dev_priv) 
	 */

	dev_priv->ring[RCS].default_context = ctx;

	ret = i915_gem_object_pin(ctx->obj, CONTEXT_ALIGN, false);

	if (ret) {

		do_destroy(ctx);

		return ret;

	}

	if (ret)

		goto err_destroy;



	ret = do_switch(ctx);

	if (ret)

		goto err_unpin;



	ret = do_switch(NULL, ctx, 0);

	if (ret) {

		i915_gem_object_unpin(ctx->obj);

		do_destroy(ctx);

	} else {

	DRM_DEBUG_DRIVER("Default HW context loaded\n");

	}

	return 0;



err_unpin:

	i915_gem_object_unpin(ctx->obj);

err_destroy:

	do_destroy(ctx);

	return ret;

}
@@ -359,17 +359,18 @@ mi_set_context(struct intel_ring_buffer *ring, 
	return ret;

}



static int do_switch(struct drm_i915_gem_object *from_obj,

		     struct i915_hw_context *to,

		     u32 seqno)

static int do_switch(struct i915_hw_context *to)

{

	struct intel_ring_buffer *ring = NULL;

	struct intel_ring_buffer *ring = to->ring;

	struct drm_i915_gem_object *from_obj = ring->last_context_obj;

	u32 hw_flags = 0;

	int ret;



	BUG_ON(to == NULL);

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



	if (from_obj == to->obj)

		return 0;



	ret = i915_gem_object_pin(to->obj, CONTEXT_ALIGN, false);

	if (ret)

		return ret;
@@ -393,7 +394,6 @@ static int do_switch(struct drm_i915_gem_object *from_obj, 
	else if (WARN_ON_ONCE(from_obj == to->obj)) /* not yet expected */

		hw_flags |= MI_FORCE_RESTORE;



	ring = to->ring;

	ret = mi_set_context(ring, to, hw_flags);

	if (ret) {

		i915_gem_object_unpin(to->obj);
@@ -407,6 +407,7 @@ static int do_switch(struct drm_i915_gem_object *from_obj, 
	 * MI_SET_CONTEXT instead of when the next seqno has completed.

	 */

	if (from_obj != NULL) {

		u32 seqno = i915_gem_next_request_seqno(ring);

		from_obj->base.read_domains = I915_GEM_DOMAIN_INSTRUCTION;

		i915_gem_object_move_to_active(from_obj, ring, seqno);

		/* As long as MI_SET_CONTEXT is serializing, ie. it flushes the
@@ -417,7 +418,7 @@ static int do_switch(struct drm_i915_gem_object *from_obj, 
		 * swapped, but there is no way to do that yet.

		 */

		from_obj->dirty = 1;

		BUG_ON(from_obj->ring != to->ring);

		BUG_ON(from_obj->ring != ring);

		i915_gem_object_unpin(from_obj);



		drm_gem_object_unreference(&from_obj->base);
@@ -448,10 +449,7 @@ int i915_switch_context(struct intel_ring_buffer *ring, 
			int to_id)

{

	struct drm_i915_private *dev_priv = ring->dev->dev_private;

	struct drm_i915_file_private *file_priv = NULL;

	struct i915_hw_context *to;

	struct drm_i915_gem_object *from_obj = ring->last_context_obj;

	int ret;



	if (dev_priv->hw_contexts_disabled)

		return 0;
@@ -459,21 +457,18 @@ int i915_switch_context(struct intel_ring_buffer *ring, 
	if (ring != &dev_priv->ring[RCS])

		return 0;



	if (file)

		file_priv = file->driver_priv;



	if (to_id == DEFAULT_CONTEXT_ID) {

		to = ring->default_context;

	} else {

		to = i915_gem_context_get(file_priv, to_id);

		if (file == NULL)

			return -EINVAL;



		to = i915_gem_context_get(file->driver_priv, to_id);

		if (to == NULL)

			return -ENOENT;

	}



	if (from_obj == to->obj)

		return 0;



	return do_switch(from_obj, to, i915_gem_next_request_seqno(to->ring));

	return do_switch(to);

}



int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,