[Intel-gfx] [PATCH] drm/i915: Don't use enums for hardware engine id

[Chris Wilson]

On Tue, Feb 28, 2017 at 02:12:09PM +0000, Michal Wajdeczko wrote:
> Generally we are using macros for any hardware identifiers as these
> may change between Gens. Do the same with hardware engine ids.
> 
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_engine_cs.c  |  2 +-
>  drivers/gpu/drm/i915/intel_ringbuffer.h | 41 ++++++++++++++++++++-------------
>  2 files changed, 26 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
> index 4db2f23..8df53ae 100644
> --- a/drivers/gpu/drm/i915/intel_engine_cs.c
> +++ b/drivers/gpu/drm/i915/intel_engine_cs.c
> @@ -29,7 +29,7 @@
>  static const struct engine_info {
>  	const char *name;
>  	unsigned exec_id;
> -	enum intel_engine_hw_id hw_id;
> +	unsigned hw_id;
>  	u32 mmio_base;
>  	unsigned irq_shift;
>  	int (*init_legacy)(struct intel_engine_cs *engine);
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
> index 3dd6eee..9cc7863 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.h
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
> @@ -186,26 +186,35 @@ struct i915_ctx_workarounds {
>  struct drm_i915_gem_request;
>  struct intel_render_state;
>  
> +
> +/*
> + * Engine IDs definitions.
> + * Keep instances of the same type engine together.
> + */
> +enum intel_engine_id {
> +	RCS = 0,
> +	BCS,
> +	VCS,
> +	VCS2,
> +#define _VCS(n) (VCS + (n))
> +	VECS
> +};
> +
> +/* Hardware Engine ID definitions */
> +#define RCS_HW		0
> +#define VCS_HW		1
> +#define BCS_HW		2
> +#define VECS_HW		3
> +#define VCS2_HW		4

So don't put them in the header if they may have inconsistent meanings.
It only a field which we supply to hardware and can simply be defined in
intel_engine_cs.c and treated as an opaque field elsewhere. We will keep
using our own classification (enum engine_id and whatnot) to refer to
the engines in the driver.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre