[Intel-gfx] [PATCH 22/53] drm/i915: Update i915_switch_context() to take a request structure

[Tomas Elf]

On 19/02/2015 17:17, John.C.Harrison at Intel.com wrote:
> From: John Harrison <John.C.Harrison at Intel.com>
>
> Now that the request is guaranteed to specify the context, it is possible to
> update the context switch code to use requests rather than ring and context
> pairs. This patch updates i915_switch_context() accordingly.
>
> Also removed the warning that the request's context must match the last context
> switch's context. As the context switch now gets the context object from the
> request structure, there is no longer any scope for the two to become out of
> step.
>
> For: VIZ-5115
> Signed-off-by: John Harrison <John.C.Harrison at Intel.com>
> ---
>   drivers/gpu/drm/i915/i915_drv.h            |    3 +--
>   drivers/gpu/drm/i915/i915_gem.c            |    4 +---
>   drivers/gpu/drm/i915/i915_gem_context.c    |   19 +++++++++----------
>   drivers/gpu/drm/i915/i915_gem_execbuffer.c |    2 +-
>   4 files changed, 12 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 618a841..e9cc343 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2992,8 +2992,7 @@ void i915_gem_context_reset(struct drm_device *dev);
>   int i915_gem_context_open(struct drm_device *dev, struct drm_file *file);
>   int i915_gem_context_enable(struct drm_i915_gem_request *req);
>   void i915_gem_context_close(struct drm_device *dev, struct drm_file *file);
> -int i915_switch_context(struct intel_engine_cs *ring,
> -			struct intel_context *to);
> +int i915_switch_context(struct drm_i915_gem_request *req);
>   struct intel_context *
>   i915_gem_context_get(struct drm_i915_file_private *file_priv, u32 id);
>   void i915_gem_context_free(struct kref *ctx_ref);
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 64288e3..0c7e1bd 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -2470,8 +2470,6 @@ int __i915_add_request(struct intel_engine_cs *ring,
>   	WARN_ON(request->batch_obj && obj);
>   	request->batch_obj = obj;
>
> -	WARN_ON(request->ctx != ring->last_context);
> -
>   	request->emitted_jiffies = jiffies;
>   	list_add_tail(&request->list, &ring->request_list);
>   	request->file_priv = NULL;
> @@ -3114,7 +3112,7 @@ int i915_gpu_idle(struct drm_device *dev)
>   			if (ret)
>   				return ret;
>
> -			ret = i915_switch_context(req->ring, ring->default_context);
> +			ret = i915_switch_context(req);
>   			if (ret) {
>   				i915_gem_request_unreference(req);
>   				return ret;
> diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
> index 04d2a20..b326f8d 100644
> --- a/drivers/gpu/drm/i915/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/i915_gem_context.c
> @@ -414,7 +414,7 @@ int i915_gem_context_enable(struct drm_i915_gem_request *req)
>
>   		ret = ring->init_context(req->ring, ring->default_context);
>   	} else
> -		ret = i915_switch_context(req->ring, ring->default_context);
> +		ret = i915_switch_context(req);
>
>   	if (ret) {
>   		DRM_ERROR("ring init context: %d\n", ret);
> @@ -693,8 +693,7 @@ unpin_out:
>
>   /**
>    * i915_switch_context() - perform a GPU context switch.
> - * @ring: ring for which we'll execute the context switch
> - * @to: the context to switch to
> + * @req: request for which we'll execute the context switch
>    *
>    * The context life cycle is simple. The context refcount is incremented and
>    * decremented by 1 and create and destroy. If the context is in use by the GPU,
> @@ -705,25 +704,25 @@ unpin_out:
>    * switched by writing to the ELSP and requests keep a reference to their
>    * context.
>    */
> -int i915_switch_context(struct intel_engine_cs *ring,
> -			struct intel_context *to)
> +int i915_switch_context(struct drm_i915_gem_request *req)
>   {
> +	struct intel_engine_cs *ring = req->ring;
>   	struct drm_i915_private *dev_priv = ring->dev->dev_private;
>
>   	WARN_ON(i915.enable_execlists);
>   	WARN_ON(!mutex_is_locked(&dev_priv->dev->struct_mutex));
>
> -	if (to->legacy_hw_ctx.rcs_state == NULL) { /* We have the fake context */
> -		if (to != ring->last_context) {
> -			i915_gem_context_reference(to);
> +	if (req->ctx->legacy_hw_ctx.rcs_state == NULL) { /* We have the fake context */
> +		if (req->ctx != ring->last_context) {
> +			i915_gem_context_reference(req->ctx);
>   			if (ring->last_context)
>   				i915_gem_context_unreference(ring->last_context);
> -			ring->last_context = to;
> +			ring->last_context = req->ctx;
>   		}
>   		return 0;
>   	}
>
> -	return do_switch(ring, to);
> +	return do_switch(req->ring, req->ctx);
>   }
>
>   static bool contexts_enabled(struct drm_device *dev)
> diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> index 2cd0579..1e2fc80 100644
> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> @@ -1190,7 +1190,7 @@ i915_gem_ringbuffer_submission(struct i915_execbuffer_params *params,
>   	if (ret)
>   		goto error;
>
> -	ret = i915_switch_context(ring, params->ctx);
> +	ret = i915_switch_context(params->request);
>   	if (ret)
>   		goto error;
>
>

Reviewed-by: Tomas Elf <tomas.elf at intel.com>

Thanks,
Tomas