Enabling / disabling DSC decompression in the branch device downstream
of the source may reset the whole branch device. To avoid this while the
streams are still active, force a modeset on all CRTC/ports connected to
this branch device.
v2:
- Check the CRTC state for each connector in the topology, instead of
the CRTC being checked for a modeset requirement. (Ville)
- Add DocBook for the new function.
Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx> (v1)
Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_display.c | 4 +
drivers/gpu/drm/i915/display/intel_dp_mst.c | 88 ++++++++++++++++++++
drivers/gpu/drm/i915/display/intel_dp_mst.h | 2 +
3 files changed, 94 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index d27afda0cfaa6..2d614180b6bdc 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -6489,6 +6489,10 @@ int intel_atomic_check(struct drm_device *dev,
if (!new_crtc_state->hw.enable || intel_crtc_needs_modeset(new_crtc_state))
continue;
+ if (intel_dp_mst_crtc_needs_modeset(state, crtc))
+ intel_modeset_pipes_in_mask_early(state, "MST topology",
+ BIT(crtc->pipe));
+
if (intel_dp_mst_is_slave_trans(new_crtc_state)) {
enum transcoder master = new_crtc_state->mst_master_transcoder;
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 9037e11ec6e0d..2313844456961 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -1596,3 +1596,91 @@ int intel_dp_mst_add_topology_state_for_crtc(struct intel_atomic_state *state,
return 0;
}
+
+static struct intel_connector *
+get_connector_in_state_for_crtc(struct intel_atomic_state *state,
+ const struct intel_crtc *crtc)
+{
+ struct drm_connector_state *old_conn_state;
+ struct drm_connector_state *new_conn_state;
+ struct drm_connector *_connector;
+ int i;
+
+ for_each_oldnew_connector_in_state(&state->base, _connector,
+ old_conn_state, new_conn_state, i) {
+ struct intel_connector *connector =
+ to_intel_connector(_connector);
+
+ if (old_conn_state->crtc == &crtc->base ||
+ new_conn_state->crtc == &crtc->base)
+ return connector;
+ }
+
+ return NULL;
+}
+
+/**
+ * intel_dp_mst_crtc_needs_modeset - check if changes in topology need to modeset the given CRTC
+ * @state: atomic state
+ * @crtc: CRTC for which to check the modeset requirement
+ *
+ * Check if any change in a MST topology requires a forced modeset on @crtc in
+ * this topology. One such change is enabling/disabling the DSC decompression
+ * state in the first branch device's UFP DPCD as required by one CRTC, while
+ * the other @crtc in the same topology is still active, requiring a full modeset
+ * on @crtc.
+ */
+bool intel_dp_mst_crtc_needs_modeset(struct intel_atomic_state *state,
+ struct intel_crtc *crtc)
+{
+ const struct intel_connector *crtc_connector;
+ const struct drm_connector_state *conn_state;
+ const struct drm_connector *_connector;
+ int i;
+
+ if (!intel_crtc_has_type(intel_atomic_get_new_crtc_state(state, crtc),
+ INTEL_OUTPUT_DP_MST))
+ return false;
+
+ crtc_connector = get_connector_in_state_for_crtc(state, crtc);
+
+ if (!crtc_connector)
+ /* None of the connectors in the topology needs modeset */
+ return false;
+
+ for_each_new_connector_in_state(&state->base, _connector, conn_state, i) {
+ const struct intel_connector *connector =
+ to_intel_connector(_connector);
+ const struct intel_crtc_state *new_crtc_state;
+ const struct intel_crtc_state *old_crtc_state;
+ struct intel_crtc *crtc_iter;
+
+ if (connector->mst_port != crtc_connector->mst_port ||
+ !conn_state->crtc)
+ continue;
+
+ crtc_iter = to_intel_crtc(conn_state->crtc);
+
+ new_crtc_state = intel_atomic_get_new_crtc_state(state, crtc_iter);
+ old_crtc_state = intel_atomic_get_old_crtc_state(state, crtc_iter);
+
+ if (!intel_crtc_needs_modeset(new_crtc_state))
+ continue;
+
+ if (old_crtc_state->dsc.compression_enable ==
+ new_crtc_state->dsc.compression_enable)
+ continue;
+ /*
+ * Toggling the decompression flag because of this stream in
+ * the first downstream branch device's UFP DPCD may reset the
+ * whole branch device. To avoid the reset while other streams
+ * are also active modeset the whole MST topology in this
+ * case.
+ */
+ if (connector->dp.dsc_decompression_aux ==
+ &connector->mst_port->aux)
+ return true;
+ }
+
+ return false;
+}
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.h b/drivers/gpu/drm/i915/display/intel_dp_mst.h
index f1815bb722672..fc5e85776a858 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.h
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.h
@@ -22,5 +22,7 @@ bool intel_dp_mst_is_slave_trans(const struct intel_crtc_state *crtc_state);
bool intel_dp_mst_source_support(struct intel_dp *intel_dp);
int intel_dp_mst_add_topology_state_for_crtc(struct intel_atomic_state *state,
struct intel_crtc *crtc);
+bool intel_dp_mst_crtc_needs_modeset(struct intel_atomic_state *state,
+ struct intel_crtc *crtc);
#endif /* __INTEL_DP_MST_H__ */
--
2.39.2
