[PATCH v3 16/16] drm/amd/display: Trigger modesets on MST DSC connectors

[David Francis]

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

Cc: Leo Li <sunpeng.li at amd.com>
Cc: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
Cc: Lyude Paul <lyude at redhat.com>
Signed-off-by: David Francis <David.Francis at amd.com>
---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 77 +++++++++++++++++++
 1 file changed, 77 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 145fd73025dc..702fb0e29053 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -6475,7 +6475,73 @@ static int do_aquire_global_lock(struct drm_device *dev,
 
 	return ret < 0 ? ret : 0;
 }
+#ifdef CONFIG_DRM_AMD_DC_DSC_SUPPORT
+/*
+ * TODO: This logic should at some point be moved into DRM
+ */
+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 drm_connector_list_iter conn_iter;
+	struct drm_crtc_state *new_crtc_state;
+	struct amdgpu_dm_connector *aconnector = NULL, *aconnector_to_add;
+	int i, j;
+	struct drm_crtc *crtcs_affected[AMDGPU_MAX_CRTCS] = { 0 };
+
+	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;
+
+	i = 0;
+	drm_connector_list_iter_begin(state->dev, &conn_iter);
+	drm_for_each_connector_iter(connector, &conn_iter) {
+		if (!connector->state || !connector->state->crtc)
+			continue;
+
+		aconnector_to_add = to_amdgpu_dm_connector(connector);
+		if (!aconnector_to_add->port)
+			continue;
+
+		if (aconnector_to_add->port->mgr != aconnector->port->mgr)
+			continue;
+
+		if (!aconnector_to_add->dc_sink)
+			continue;
+
+		if (!aconnector_to_add->dc_sink->sink_dsc_caps.dsc_dec_caps.is_dsc_supported)
+			continue;
+
+		if (i >= AMDGPU_MAX_CRTCS)
+			continue;
+
+		crtcs_affected[i] = connector->state->crtc;
+		i++;
+	}
+	drm_connector_list_iter_end(&conn_iter);
+
+	for (j = 0; j < i; j++) {
+		new_crtc_state = drm_atomic_get_crtc_state(state, crtcs_affected[j]);
+		if (IS_ERR(new_crtc_state))
+			return PTR_ERR(new_crtc_state);
 
+		new_crtc_state->mode_changed = true;
+	}
+
+	return 0;
+
+}
+#endif
 static void get_freesync_config_for_crtc(
 	struct dm_crtc_state *new_crtc_state,
 	struct dm_connector_state *new_con_state)
@@ -7160,6 +7226,17 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
 	if (ret)
 		goto fail;
 
+#ifdef CONFIG_DRM_AMD_DC_DSC_SUPPORT
+	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;
+			}
+		}
+	}
+#endif
 	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