From: Aurabindo Pillai <aurabindo.pil...@amd.com>

[ Upstream commit e6142dd511425cb827b5db869f489eb81f5f994d ]

[why]
During hotplug, a DP port may be connected to the sink through
passive adapter which does not support DPCD reads. Issuing reads
without checking for this condition will result in errors

[how]
Ensure the link is in aux_mode before initiating operation that result
in a DPCD read.

Signed-off-by: Aurabindo Pillai <aurabindo.pil...@amd.com>
Reviewed-by: Harry Wentland <harry.wentl...@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pil...@amd.com>
Signed-off-by: Alex Deucher <alexander.deuc...@amd.com>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c   | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c 
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 5e27a67fbc58..0cd11d3d4cf4 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1941,17 +1941,22 @@ amdgpu_dm_update_connector_after_detect(struct 
amdgpu_dm_connector *aconnector)
                dc_sink_retain(aconnector->dc_sink);
                if (sink->dc_edid.length == 0) {
                        aconnector->edid = NULL;
-                       drm_dp_cec_unset_edid(&aconnector->dm_dp_aux.aux);
+                       if (aconnector->dc_link->aux_mode) {
+                               drm_dp_cec_unset_edid(
+                                       &aconnector->dm_dp_aux.aux);
+                       }
                } else {
                        aconnector->edid =
-                               (struct edid *) sink->dc_edid.raw_edid;
-
+                               (struct edid *)sink->dc_edid.raw_edid;
 
                        drm_connector_update_edid_property(connector,
-                                       aconnector->edid);
-                       drm_dp_cec_set_edid(&aconnector->dm_dp_aux.aux,
-                                           aconnector->edid);
+                                                          aconnector->edid);
+
+                       if (aconnector->dc_link->aux_mode)
+                               drm_dp_cec_set_edid(&aconnector->dm_dp_aux.aux,
+                                                   aconnector->edid);
                }
+
                amdgpu_dm_update_freesync_caps(connector, aconnector->edid);
 
        } else {
-- 
2.25.1

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