[PATCH v9 18/18] drm/amd/display: Trigger modesets on MST DSC connectors

[mikita.lipski at amd.com]

From: Mikita Lipski <mikita.lipski at amd.com>

Whenever a connector on an MST network is attached, detached, or
undergoes a modeset, the DSC configs for each stream on that
topology will be recalculated. This can change their required
bandwidth, requiring a full reprogramming, as though a modeset
was performed, even if that stream did not change timing.

Therefore, whenever a crtc has drm_atomic_crtc_needs_modeset,
for each crtc that shares a MST topology with that stream and
supports DSC, add that crtc (and all affected connectors and
planes) to the atomic state and set mode_changed on its state

v2: Do this check only on Navi and before adding connectors
and planes on modesetting crtcs

v3: Call the drm_dp_mst_add_affected_dsc_crtcs() to update
all affected CRTCs

Reviewed-by: Lyude Paul <lyude at redhat.com>
Signed-off-by: David Francis <David.Francis at amd.com>
Signed-off-by: Mikita Lipski <mikita.lipski at amd.com>
---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 33 +++++++++++++++++++
 1 file changed, 33 insertions(+)

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 2ac3a2f0b452..909665427110 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -7930,6 +7930,29 @@ dm_determine_update_type_for_commit(struct amdgpu_display_manager *dm,
 	return ret;
 }
 
+static int add_affected_mst_dsc_crtcs(struct drm_atomic_state *state, struct drm_crtc *crtc)
+{
+	struct drm_connector *connector;
+	struct drm_connector_state *conn_state;
+	struct amdgpu_dm_connector *aconnector = NULL;
+	int i;
+	for_each_new_connector_in_state(state, connector, conn_state, i) {
+		if (conn_state->crtc != crtc)
+			continue;
+
+		aconnector = to_amdgpu_dm_connector(connector);
+		if (!aconnector->port)
+			aconnector = NULL;
+		else
+			break;
+	}
+
+	if (!aconnector)
+		return 0;
+
+	return drm_dp_mst_add_affected_dsc_crtcs(state, &aconnector->mst_mgr);
+}
+
 /**
  * amdgpu_dm_atomic_check() - Atomic check implementation for AMDgpu DM.
  * @dev: The DRM device
@@ -7982,6 +8005,16 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
 	if (ret)
 		goto fail;
 
+	if (adev->asic_type >= CHIP_NAVI10) {
+		for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
+			if (drm_atomic_crtc_needs_modeset(new_crtc_state)) {
+				ret = add_affected_mst_dsc_crtcs(state, crtc);
+				if (ret)
+					goto fail;
+			}
+		}
+	}
+
 	for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
 		if (!drm_atomic_crtc_needs_modeset(new_crtc_state) &&
 		    !new_crtc_state->color_mgmt_changed &&
-- 
2.17.1