drm/i915/vrr: Avoid vrr for PCON with HDMI2.1 sink

Currently we do not support VRR with HDMI so skip vrr compute
config step for all DP branch devices.

v2: Restrict VRR on all DP branch devices instead for checking only for
    HDMI. (Ville)

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260424090942.3060291-2-ankit.k.nautiyal@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
index fae1186a90b2be2d823cb91bad442275736125c1..1b09992ce9fddd0aa5c7e77ea247b6a73f6ffc54 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_vrr.c
+++ b/drivers/gpu/drm/i915/display/intel_vrr.c
@@ -55,6 +55,16 @@ bool intel_vrr_is_capable(struct intel_connector *connector)
                if (connector->mst.dp)
                        return false;
                intel_dp = intel_attached_dp(connector);
+               /*
+                * Among non-MST DP branch devices, only an HDMI 2.1 sink connected
+                * via a PCON could support VRR. However, supporting VRR through a
+                * PCON requires non-trivial changes that are not implemented yet.
+                * Until that support exists, avoid VRR on all DP branch devices.
+                *
+                * TODO: Add support for VRR for DP->HDMI 2.1 PCON.
+                */
+               if (drm_dp_is_branch(intel_dp->dpcd))
+                       return false;
 
                if (!drm_dp_sink_can_do_video_without_timing_msa(intel_dp->dpcd))
                        return false;