Improve handling of the display

 - Blank the display when locking to prevent burn-in
 - Delay turning the display on until *exactly* after the first lvgl flush
 - Init the display in the ui task to avoid blocking the rest of boot

4 files changed, 22 insertions, 10 deletions

diff --git a/src/ui/include/ui_events.hpp b/src/ui/include/ui_events.hpp
index 81e0543a..3d794edc 100644
--- a/src/ui/include/ui_events.hpp
+++ b/src/ui/include/ui_events.hpp
@@ -8,7 +8,9 @@
 
 #include <memory>
 #include "database.hpp"
+#include "gpios.hpp"
 #include "index.hpp"
+#include "nvs.hpp"
 #include "screen.hpp"
 #include "tinyfsm.hpp"
 
@@ -32,6 +34,11 @@ struct DumpLuaStack : tinyfsm::Event {};
 
 namespace internal {
 
+struct InitDisplay : tinyfsm::Event {
+  drivers::IGpios& gpios;
+  drivers::NvsStorage& nvs;
+};
+
 struct ReindexDatabase : tinyfsm::Event {};
 
 struct BackPressed : tinyfsm::Event {};
diff --git a/src/ui/include/ui_fsm.hpp b/src/ui/include/ui_fsm.hpp
index 8eafc6e0..325aea8f 100644
--- a/src/ui/include/ui_fsm.hpp
+++ b/src/ui/include/ui_fsm.hpp
@@ -70,6 +70,7 @@ class UiState : public tinyfsm::Fsm<UiState> {
   void react(const system_fsm::KeyLockChanged&);
   void react(const system_fsm::SamdUsbStatusChanged&);
 
+  void react(const internal::InitDisplay&);
   void react(const internal::DismissAlerts&);
 
   void react(const database::event::UpdateStarted&);
diff --git a/src/ui/lvgl_task.cpp b/src/ui/lvgl_task.cpp
index 4cf25c15..51da0179 100644
--- a/src/ui/lvgl_task.cpp
+++ b/src/ui/lvgl_task.cpp
@@ -84,7 +84,6 @@ auto UiTask::Main() -> void {
 }
 
 auto UiTask::input(std::shared_ptr<input::LvglInputDriver> input) -> void {
-  assert(current_screen_);
   input_ = input;
 }
 
diff --git a/src/ui/ui_fsm.cpp b/src/ui/ui_fsm.cpp
index 1305e764..ceeb194d 100644
--- a/src/ui/ui_fsm.cpp
+++ b/src/ui/ui_fsm.cpp
@@ -267,6 +267,15 @@ lua::Property UiState::sUsbMassStorageBusy{false};
 
 auto UiState::InitBootSplash(drivers::IGpios& gpios, drivers::NvsStorage& nvs)
     -> bool {
+  events::Ui().Dispatch(internal::InitDisplay{
+      .gpios = gpios,
+      .nvs = nvs,
+  });
+  sTask.reset(UiTask::Start());
+  return true;
+}
+
+void UiState::react(const internal::InitDisplay& ev) {
   // Init LVGL first, since the display driver registers itself with LVGL.
   lv_init();
 
@@ -275,19 +284,15 @@ auto UiState::InitBootSplash(drivers::IGpios& gpios, drivers::NvsStorage& nvs)
   // HACK: correct the display size for our prototypes.
   // nvs.DisplaySize({161, 130});
 
-  auto actual_size = nvs.DisplaySize();
+  auto actual_size = ev.nvs.DisplaySize();
   init_data.width = actual_size.first.value_or(init_data.width);
   init_data.height = actual_size.second.value_or(init_data.height);
-
-  sDisplay.reset(drivers::Display::Create(gpios, init_data));
-  if (sDisplay == nullptr) {
-    return false;
-  }
+  sDisplay.reset(drivers::Display::Create(ev.gpios, init_data));
 
   sCurrentScreen.reset(new screens::Splash());
-  sTask.reset(UiTask::Start());
-  sDisplay->SetDisplayOn(!gpios.IsLocked());
-  return true;
+
+  // Display will only actually come on after LVGL finishes its first flush.
+  sDisplay->SetDisplayOn(!ev.gpios.IsLocked());
 }
 
 void UiState::PushScreen(std::shared_ptr<Screen> screen) {