[Intel-gfx] [PATCH] drm/i915: Use enum plane_id for frontbuffer tracking

[Chris Wilson]

Quoting Ville Syrjala (2018-01-23 18:33:43)
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Replace the ad-hoc plane indexing scheme used by the frontbuffer
> tracking with enum plane_id.
> 
> The old video overlay not being part of the plane_id namespace
> will just be given the high bit.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h      | 11 +++--------
>  drivers/gpu/drm/i915/intel_display.c |  4 ++--
>  drivers/gpu/drm/i915/intel_fbc.c     |  2 +-
>  drivers/gpu/drm/i915/intel_sprite.c  |  4 +++-
>  4 files changed, 9 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 8333692dac5a..bd545b1c9546 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2404,16 +2404,11 @@ enum hdmi_force_audio {
>   *
>   * We have one bit per pipe and per scanout plane type.
>   */
> -#define INTEL_MAX_SPRITE_BITS_PER_PIPE 5
>  #define INTEL_FRONTBUFFER_BITS_PER_PIPE 8

I would feel safer with a BUILD_BUG_ON to catch plane_id overflowing
INTEL_FRONTBUFFER_BITS_PER_PIPE (-1 for the overlay reservation).

> -#define INTEL_FRONTBUFFER_PRIMARY(pipe) \
> -       (1 << (INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe)))
> -#define INTEL_FRONTBUFFER_CURSOR(pipe) \
> -       (1 << (1 + (INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe))))
> -#define INTEL_FRONTBUFFER_SPRITE(pipe, plane) \
> -       (1 << (2 + plane + (INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe))))
> +#define INTEL_FRONTBUFFER(pipe, plane_id) \
> +       (1 << ((plane_id) + INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe)))
>  #define INTEL_FRONTBUFFER_OVERLAY(pipe) \
> -       (1 << (2 + INTEL_MAX_SPRITE_BITS_PER_PIPE + (INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe))))
> +       (1 << (INTEL_FRONTBUFFER_BITS_PER_PIPE - 1 + INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe)))
>  #define INTEL_FRONTBUFFER_ALL_MASK(pipe) \
>         (0xff << (INTEL_FRONTBUFFER_BITS_PER_PIPE * (pipe)))

The conversion looks straightforward nevertheless, and indeed no reason
to have move than one indexing id for a plane.
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris