Re: [PATCH 3/4] drm/i915/dp: Allow AS_SDP only if panel replay + auxless alpm is supported

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

On Tue, Nov 11, 2025 at 03:00:06PM +0530, Ankit Nautiyal wrote:
> Adaptive Sync SDP is required when Panel replay is active and for
> supporting VRR on PCON.
> 
> Since VRR on PCON still needs some effort, enable adaptive sync SDP only
> when Panel replay with ALPM-Auxless is supported.
> 
> Set the AS_SDP mode for Fixed Vtotal mode for fixed refresh rate case.
> 
> v2: Remove redundant target_rr assignments. (Ville)
> 
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 92a553a76b57..2852a1d9f157 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -2935,7 +2935,15 @@ static void intel_dp_compute_as_sdp(struct intel_dp *intel_dp,
>  	const struct drm_display_mode *adjusted_mode =
>  		&crtc_state->hw.adjusted_mode;
>  
> -	if (!crtc_state->vrr.enable || !intel_dp->as_sdp_supported)
> +	if (!intel_dp->as_sdp_supported)
> +		return;
> +
> +	/*
> +	 * Support Adaptive-Sync SDP only for PR+AUX-less ALPM for now.
> +	 * It can be enabled for PCON + VRR, but that is currently not supported.
> +	 */
> +	if (!CAN_PANEL_REPLAY(intel_dp) ||
> +	    !intel_alpm_aux_less_wake_supported(intel_dp))
>  		return;
>  
>  	crtc_state->infoframes.enable |= intel_hdmi_infoframe_enable(DP_SDP_ADAPTIVE_SYNC);
> @@ -2949,9 +2957,10 @@ static void intel_dp_compute_as_sdp(struct intel_dp *intel_dp,
>  		as_sdp->mode = DP_AS_SDP_FAVT_TRR_REACHED;
>  		as_sdp->target_rr = drm_mode_vrefresh(adjusted_mode);
>  		as_sdp->target_rr_divider = true;
> -	} else {
> +	} else if (crtc_state->vrr.enable) {
>  		as_sdp->mode = DP_AS_SDP_AVT_DYNAMIC_VTOTAL;
> -		as_sdp->target_rr = 0;
> +	} else {
> +		as_sdp->mode = DP_AS_SDP_AVT_FIXED_VTOTAL;

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

But we're still not configuring DOWNSPREAD_CTRL correctly so PR+VRR
seems to be busted.

>  	}
>  }
>  
> -- 
> 2.45.2

-- 
Ville Syrjälä
Intel