Re: [PATCH 11/14] drm/i915/dp: Program AS SDP DB[1:0] for PR with Link off

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

On 2/26/2026 9:44 PM, Ville Syrjälä wrote:
> On Mon, Feb 23, 2026 at 07:14:28PM +0530, Ankit Nautiyal wrote:
>> For Panel Replay with AUX-less ALPM (link-off PR), the source must send
>> Adaptive-Sync SDP v2. Program DB[1:0] per DP spec v2.1:
>> - VRR AVT: 00b (variable VTotal)
>> - VRR FAVT: 10b/11b (TRR not reached/reached)
>> - Fixed timing with PR link-off (VRR off): 01b (AS disabled; VTotal fixed)
>>
>> Select SDP version v2 whenever PR link-off or VRR is active, otherwise v1,
>> and program the AS SDP DB[1:0] bits.
>>
>> Also, drop the redundant target_rr assignment.
>>
>> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
>> ---
>>   drivers/gpu/drm/i915/display/intel_dp.c | 7 ++++---
>>   1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
>> index 5952db6197cf..ad2aceb526ff 100644
>> --- a/drivers/gpu/drm/i915/display/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
>> @@ -3139,7 +3139,7 @@ static void intel_dp_compute_as_sdp(struct intel_dp *intel_dp,
>>   	as_sdp->duration_incr_ms = 0;
>>   	as_sdp->version = 0x2;
>>   
>> -	if (crtc_state->vrr.enable)
>> +	if (crtc_state->vrr.enable || intel_psr_is_pr_with_link_off(crtc_state))
>>   		as_sdp->version = 0x2;
>>   	else
>>   		as_sdp->version = 0x1;
>> @@ -3154,9 +3154,10 @@ 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 if (intel_psr_is_pr_with_link_off(crtc_state)) {
>> +		as_sdp->mode = DP_AS_SDP_AVT_FIXED_VTOTAL;
>>   	}
>   else {
>    what now?
>   }

Hmm I think with always enable AS SDP the else part would naturally become:

as_sdp->mode = DP_AS_SDP_AVT_FIXED_VTOTAL;


Regards,
Ankit


>>   }
>>   
>> -- 
>> 2.45.2