Re: [PATCH v2] drm/i915/display: update to the BW buddy configuration

[Jani Nikula <jani.nikula@linux.intel.com>]

On Tue, 16 Jun 2026, Vinod Govindapillai <vinod.govindapillai@intel.com> wrote:
> Bspec has been updated for xe2_lpd+ platforms on how to handle
> the bw buddy prgramming in case no matching memory configuration
> is found w.r.t the current page mask table. The recommendation
> is to keep the default settings for the related registers as it
> is without explicitly disabling the bw buddy.
>
> v2: removed extra explanation
>
> Bspec: 68871
> Suggested-by: Ville Syrjala <ville.syrjala@intel.com>
> Signed-off-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display_power.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c b/drivers/gpu/drm/i915/display/intel_display_power.c
> index 2e51dfcd5dce..3d348c5decee 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_power.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_power.c
> @@ -1634,9 +1634,12 @@ static void tgl_bw_buddy_init(struct intel_display *display)
>  	if (table[config].page_mask == 0) {
>  		drm_dbg_kms(display->drm,
>  			    "Unknown memory configuration; disabling address buddy logic.\n");

The debug logging becomes misleading for display >= 20.

BR,
Jani.

> -		for_each_set_bit(i, &abox_mask, BITS_PER_TYPE(abox_mask))
> -			intel_de_write(display, BW_BUDDY_CTL(i),
> -				       BW_BUDDY_DISABLE);
> +
> +		if (DISPLAY_VER(display) < 20) {
> +			for_each_set_bit(i, &abox_mask, BITS_PER_TYPE(abox_mask))
> +				intel_de_write(display, BW_BUDDY_CTL(i),
> +					       BW_BUDDY_DISABLE);
> +		}
>  	} else {
>  		for_each_set_bit(i, &abox_mask, BITS_PER_TYPE(abox_mask)) {
>  			intel_de_write(display, BW_BUDDY_PAGE_MASK(i),

-- 
Jani Nikula, Intel