Re: [PATCH 2/3] drm/i915/display: duplicate 128-byte Y-tiling feature check

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Fri, Oct 10, 2025 at 02:07:52PM +0300, Jani Nikula wrote:
> We should try to get rid of checks that depend on struct
> drm_i915_private (or struct xe_device) in display
> code. HAS_128_BYTE_Y_TILING() is one of them. In the interest of
> simplicity, just duplicate the check as HAS_128B_Y_TILING() in display.
> 
> v2: gen2 also has 128-byte Y-tile
> 
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display_device.h | 1 +
>  drivers/gpu/drm/i915/display/intel_fb.c             | 3 +--
>  drivers/gpu/drm/xe/compat-i915-headers/i915_drv.h   | 1 -
>  3 files changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display_device.h b/drivers/gpu/drm/i915/display/intel_display_device.h
> index 0e062753cf9b..9960ac13a6dd 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_device.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_device.h
> @@ -142,6 +142,7 @@ struct intel_display_platforms {
>  	func(overlay_needs_physical); \
>  	func(supports_tv);
>  
> +#define HAS_128B_Y_TILING(__display)	(!(__display)->platform.i915g && !(__display)->platform.i915gm)
>  #define HAS_4TILE(__display)		((__display)->platform.dg2 || DISPLAY_VER(__display) >= 14)
>  #define HAS_ASYNC_FLIPS(__display)	(DISPLAY_VER(__display) >= 5)
>  #define HAS_AS_SDP(__display)		(DISPLAY_VER(__display) >= 13)
> diff --git a/drivers/gpu/drm/i915/display/intel_fb.c b/drivers/gpu/drm/i915/display/intel_fb.c
> index 3bfd211d64ba..7388791dfde0 100644
> --- a/drivers/gpu/drm/i915/display/intel_fb.c
> +++ b/drivers/gpu/drm/i915/display/intel_fb.c
> @@ -777,7 +777,6 @@ unsigned int
>  intel_tile_width_bytes(const struct drm_framebuffer *fb, int color_plane)
>  {
>  	struct intel_display *display = to_intel_display(fb->dev);
> -	struct drm_i915_private *i915 = to_i915(display->drm);
>  	unsigned int cpp = fb->format->cpp[color_plane];
>  
>  	switch (fb->modifier) {
> @@ -814,7 +813,7 @@ intel_tile_width_bytes(const struct drm_framebuffer *fb, int color_plane)
>  			return 64;
>  		fallthrough;
>  	case I915_FORMAT_MOD_Y_TILED:
> -		if (HAS_128_BYTE_Y_TILING(i915))
> +		if (HAS_128B_Y_TILING(display))
>  			return 128;
>  		else
>  			return 512;

I suppose we could just assume 128 byte Y-tile in the display
code since Y-tiled scanout wasn't even a thing before skl.
Ie. the else branch here should be dead code in reality.

But this isn't incorrect, so
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> diff --git a/drivers/gpu/drm/xe/compat-i915-headers/i915_drv.h b/drivers/gpu/drm/xe/compat-i915-headers/i915_drv.h
> index b8269391bc69..be3edf20de22 100644
> --- a/drivers/gpu/drm/xe/compat-i915-headers/i915_drv.h
> +++ b/drivers/gpu/drm/xe/compat-i915-headers/i915_drv.h
> @@ -36,6 +36,5 @@ static inline struct drm_i915_private *to_i915(const struct drm_device *dev)
>  #define IS_MOBILE(xe) (xe && 0)
>  
>  #define HAS_FLAT_CCS(xe) (xe_device_has_flat_ccs(xe))
> -#define HAS_128_BYTE_Y_TILING(xe) (xe || 1)
>  
>  #endif
> -- 
> 2.47.3

-- 
Ville Syrjälä
Intel