[PATCH 4/4] drm/i915/panel: sync panel prepared state at register

[Jani Nikula]

If the panel is enabled at probe, and we take over the hardware state,
the drm_panel prepared state will be out of sync. We'll need to notify
drm_panel framework about the state at probe, so it can in turn notify
the panel followers.

Cc: Lee Shawn C <shawn.c....@intel.com>
Signed-off-by: Jani Nikula <jani.nik...@intel.com>
---
 drivers/gpu/drm/i915/display/intel_panel.c | 41 ++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_panel.c 
b/drivers/gpu/drm/i915/display/intel_panel.c
index b1d549e6cf53..f956919dc648 100644
--- a/drivers/gpu/drm/i915/display/intel_panel.c
+++ b/drivers/gpu/drm/i915/display/intel_panel.c
@@ -463,6 +463,45 @@ void intel_panel_fini(struct intel_connector *connector)
        }
 }
 
+/*
+ * If the panel was already enabled at probe, and we took over the state, the
+ * panel prepared state is out of sync, and the panel followers won't be
+ * notified. We need to call drm_panel_prepare() on enabled panels.
+ *
+ * It would be natural to handle this e.g. in the connector ->sync_state hook 
at
+ * intel_modeset_readout_hw_state(), but that's unfortunately too early. We
+ * don't have drm_connector::kdev at that time. For now, figure out the state 
at
+ * ->late_register, and sync there.
+ */
+static void intel_panel_sync_state(struct intel_connector *connector)
+{
+       struct intel_display *display = to_intel_display(connector);
+       struct drm_connector_state *conn_state;
+       struct intel_crtc *crtc;
+       int ret;
+
+       ret = drm_modeset_lock(&display->drm->mode_config.connection_mutex, 
NULL);
+       if (ret)
+               return;
+
+       conn_state = connector->base.state;
+
+       crtc = to_intel_crtc(conn_state->crtc);
+       if (crtc) {
+               struct intel_crtc_state *crtc_state;
+
+               crtc_state = to_intel_crtc_state(crtc->base.state);
+
+               if (crtc_state->hw.active) {
+                       drm_dbg_kms(display->drm, "[CONNECTOR:%d:%s] Panel 
prepare\n",
+                                   connector->base.base.id, 
connector->base.name);
+                       intel_panel_prepare(crtc_state, conn_state);
+               }
+       }
+
+       drm_modeset_unlock(&display->drm->mode_config.connection_mutex);
+}
+
 const struct drm_panel_funcs dummy_panel_funcs = {
 };
 
@@ -513,6 +552,8 @@ int intel_panel_register(struct intel_connector *connector)
                drm_dbg_kms(display->drm, "[CONNECTOR:%d:%s] Registered panel 
device '%s', has fwnode: %s\n",
                            connector->base.base.id, connector->base.name,
                            dev_name(dev), str_yes_no(dev_fwnode(dev)));
+
+               intel_panel_sync_state(connector);
        }
 
 out:
-- 
2.39.5