Re: [PATCH 2/5] drm/i915/dp: Allow AS_SDP only if panel replay + auxless alpm is supported

["Nautiyal, Ankit K" <ankit.k.nautiyal@intel.com>]

On 10/30/2025 1:53 PM, Ville Syrjälä wrote:
> On Thu, Oct 30, 2025 at 10:47:52AM +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.
> AFAICS we don't actually check for PCON vs. not anywhere, and thus
> we are in fact allowing VRR with PCON. Or am I missign some check
> somewhere?

No you are in fact right. I had a patch to avoid vrr on PCON  in 
intel_vrr_is_capable() in the VRR timing generator series, but 
missed/dropped somewhere.

I will add that patch before this change.


Regards,

Ankit

>
>> 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 c013eb2e18a1..b5b855453845 100644
>> --- a/drivers/gpu/drm/i915/display/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
>> @@ -2934,7 +2934,15 @@ 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);
>> @@ -2948,9 +2956,10 @@ 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;
>>   	}
>>   }
>>   
>> -- 
>> 2.45.2