drm/i915/dp_mst: Verify the link status always the same way

The MST link status should be always verified from the same DPCD
registers after link training. Atm, both the legacy (0x202 - 0x205) and
the ESI (0x200C - 0x200F) link status registers are used. Use always the
latter ESI version of link status registers.

v2: Propagate error from intel_dp_read_link_status(). (Jani, Luca)

Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260225164618.1261368-3-imre.deak@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 9dbc44cbe8c7bedb773bc2b55dc3bafc16cf4087..ac6cacd19d17d89ffff61df46d026108c6d6e17a 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -5568,6 +5568,23 @@ intel_dp_handle_hdmi_link_status_change(struct intel_dp *intel_dp)
        }
 }
 
+static int
+intel_dp_read_link_status(struct intel_dp *intel_dp, u8 link_status[DP_LINK_STATUS_SIZE])
+{
+       int err;
+
+       memset(link_status, 0, DP_LINK_STATUS_SIZE);
+
+       if (intel_dp_mst_active_streams(intel_dp) > 0)
+               err = drm_dp_dpcd_read_data(&intel_dp->aux, DP_LANE0_1_STATUS_ESI,
+                                           link_status, DP_LINK_STATUS_SIZE - 2);
+       else
+               err = drm_dp_dpcd_read_phy_link_status(&intel_dp->aux, DP_PHY_DPRX,
+                                                      link_status);
+
+       return err;
+}
+
 static bool
 intel_dp_needs_link_retrain(struct intel_dp *intel_dp)
 {
@@ -5590,8 +5607,7 @@ intel_dp_needs_link_retrain(struct intel_dp *intel_dp)
        if (intel_dp->link.force_retrain)
                return true;
 
-       if (drm_dp_dpcd_read_phy_link_status(&intel_dp->aux, DP_PHY_DPRX,
-                                            link_status) < 0)
+       if (intel_dp_read_link_status(intel_dp, link_status) < 0)
                return false;
 
        /*