drm/i915/dp: Restore the missing check for intel_dp_has_joiner

Commit ad121a62d566 ("drm/i915/dp: Rework pipe joiner logic in mode_valid")
replaced intel_dp_num_joined_pipes() with an explicit joiner candidate
iteration. The previous code implicitly checked for DP joiner capability
via intel_dp_has_joiner(), but this check was lost during the refactor.

Restore the missing intel_dp_has_joiner() check in intel_dp_can_join() so
that DP specific joiner conditions are taken into account.

v2: Derive intel_dp from intel_attached_dp(). (Imre)

Fixes: ad121a62d566 ("drm/i915/dp: Rework pipe joiner logic in mode_valid")
Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260206044753.808631-1-ankit.k.nautiyal@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 08e834dbc42a3e1ec658f9c3fbca0f3df867be59..4b786706ea2de0b3755ff4f8e2393db06844d0ec 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -1397,9 +1397,14 @@ bool intel_dp_has_dsc(const struct intel_connector *connector)
 }
 
 static
-bool intel_dp_can_join(struct intel_display *display,
+bool intel_dp_can_join(struct intel_dp *intel_dp,
                       int num_joined_pipes)
 {
+       struct intel_display *display = to_intel_display(intel_dp);
+
+       if (num_joined_pipes > 1 && !intel_dp_has_joiner(intel_dp))
+               return false;
+
        switch (num_joined_pipes) {
        case 1:
                return true;
@@ -7220,8 +7225,9 @@ bool intel_dp_joiner_candidate_valid(struct intel_connector *connector,
                                     int num_joined_pipes)
 {
        struct intel_display *display = to_intel_display(connector);
+       struct intel_dp *intel_dp = intel_attached_dp(connector);
 
-       if (!intel_dp_can_join(display, num_joined_pipes))
+       if (!intel_dp_can_join(intel_dp, num_joined_pipes))
                return false;
 
        if (hdisplay > num_joined_pipes * intel_dp_max_hdisplay_per_pipe(display))