[PATCH 23/26] drm/i915/dp: Program AS SDP DB[1:0] for PR with Link off

Ankit Nautiyal
2026-04-08T08:58:37Z

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)

Also, drop the redundant target_rr assignment.

v2: Fix the else case. (Ville)

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
drivers/gpu/drm/i915/display/intel_dp.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 1e56de9c3ce3..754aa3f6427e 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -3166,9 +3166,10 @@ 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