[Intel-gfx] [PATCH] drm/i915: Introduce struct class_instance for engines across the uAPI

[Tvrtko Ursulin]

+Tony to comment on the media-driver views on this.

+Manually re-adding original Cc which did not appear for me from the ML.

On 12/04/2019 07:51, Chris Wilson wrote:
> SSEU reprogramming of the context introduced the notion of engine class
> and instance for a forwards compatible method of describing any engine
> beyond the old execbuf interface. We wish to adopt this class:instance
> description for more interfaces, so pull it out into a separate type for
> userspace convenience.
> 
> References: e46c2e99f600 ("drm/i915: Expose RPCS (SSEU) configuration to userspace (Gen11 only)")
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Cc: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
> Cc: Dmitry Rogozhkin <dmitry.v.rogozhkin at intel.com>
> Cc: Andi Shyti <andi at etezian.org>
> ---
> Commit e46c2e99f600 ("drm/i915: Expose RPCS (SSEU) configuration to
> userspace (Gen11 only)") is for v5.1, so we still do have a tiny bit of
> time to enact this change.
> ---
>   drivers/gpu/drm/i915/i915_gem_context.c |  8 ++++----
>   include/uapi/drm/i915_drm.h             | 11 +++++++++--
>   2 files changed, 13 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
> index 7fc34ab6df87..dd728b26b5aa 100644
> --- a/drivers/gpu/drm/i915/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/i915_gem_context.c
> @@ -1386,8 +1386,8 @@ static int set_sseu(struct i915_gem_context *ctx,
>   		return -EINVAL;
>   
>   	engine = intel_engine_lookup_user(i915,
> -					  user_sseu.engine_class,
> -					  user_sseu.engine_instance);
> +					  user_sseu.engine.engine_class,
> +					  user_sseu.engine.engine_instance);
>   	if (!engine)
>   		return -EINVAL;
>   
> @@ -1626,8 +1626,8 @@ static int get_sseu(struct i915_gem_context *ctx,
>   		return -EINVAL;
>   
>   	engine = intel_engine_lookup_user(ctx->i915,
> -					  user_sseu.engine_class,
> -					  user_sseu.engine_instance);
> +					  user_sseu.engine.engine_class,
> +					  user_sseu.engine.engine_instance);
>   	if (!engine)
>   		return -EINVAL;
>   
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index 52051d24d89d..f6369c462458 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -1500,6 +1500,14 @@ struct drm_i915_gem_context_param {
>   	__u64 value;
>   };
>   
> +union drm_i915_engine_class_instance {
> +	struct i915_engine_class_instance {
> +		__u16 engine_class;
> +		__u16 engine_instance;
> +	} class_instance;
> +	__u32 ci;

Is "ci" class instance or something to satisfy the test farm and what is 
the purpose for the union?

> +};
> +
>   /**
>    * Context SSEU programming
>    *
> @@ -1525,8 +1533,7 @@ struct drm_i915_gem_context_param_sseu {
>   	/*
>   	 * Engine class & instance to be configured or queried.
>   	 */
> -	__u16 engine_class;
> -	__u16 engine_instance;
> +	struct i915_engine_class_instance engine;
>   
>   	/*
>   	 * Unused for now. Must be cleared to zero.
> 

Regards,

Tvrtko