drm/amd/display: TMDS Fallback transition

[Why]
HDMI requires fallback to TMDS by redetection
in order to switch PHY settings.
This avoids black out when link training fail
during mode setting, link quality update,
disable driver sequence.

[How]
Allow driver to redetect HDMI displays
based on retraining or fallback mechanism.

Signed-off-by: Chris Park <Chris.Park@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index 9d7333a..db741e4 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -159,7 +159,20 @@ static bool validate_dsc_caps_on_connector(struct amdgpu_dm_connector *aconnecto
        u8 dsc_caps[16] = { 0 };
 
        aconnector->dsc_aux = drm_dp_mst_dsc_aux_for_port(port);
+#if defined(CONFIG_HP_HOOK_WORKAROUND)
+       /*
+        * drm_dp_mst_dsc_aux_for_port() will return NULL for certain configs
+        * because it only check the dsc/fec caps of the "port variable" and not the dock
+        *
+        * This case will return NULL: DSC capabe MST dock connected to a non fec/dsc capable display
+        *
+        * Workaround: explicitly check the use case above and use the mst dock's aux as dsc_aux
+        *
+        */
 
+       if (!aconnector->dsc_aux && !port->parent->port_parent)
+               aconnector->dsc_aux = &aconnector->mst_port->dm_dp_aux.aux;
+#endif
        if (!aconnector->dsc_aux)
                return false;
 

diff --git a/drivers/gpu/drm/amd/display/dc/dc_link.h b/drivers/gpu/drm/amd/display/dc/dc_link.h
index e002ef7..266b93a 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/dc_link.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_link.h
@@ -237,6 +237,8 @@ enum dc_detect_reason {
        DETECT_REASON_BOOT,
        DETECT_REASON_HPD,
        DETECT_REASON_HPDRX,
+       DETECT_REASON_FALLBACK,
+       DETECT_REASON_RETRAIN
 };
 
 bool dc_link_detect(struct dc_link *dc_link, enum dc_detect_reason reason);