From ee1f034c5966ee0f8ead4f5f70c5b94aa73bf779 Mon Sep 17 00:00:00 2001
From: Paulus Schoutsen <balloob@gmail.com>
Date: Fri, 3 Jul 2026 18:12:46 -0400
Subject: [PATCH] Defer BLE-callback display teardown and MSD update to the
 main loop (ESP32)

onConnect() and onDisconnect() run in the BLE host task. onConnect() called
updatemsdata() (I2C sensor reads + shared-state mutation) and onDisconnect()
called cleanupDirectWriteState() (bbepSleep/SPI.end/pwrmgm) directly. Both
race loop(): a disconnect firing while loop() is mid bbepWriteData powers the
panel down under an in-flight SPI transfer and clears state the handler is
still using; onConnect's updatemsdata races the loop's I2C/statics.

Set pending flags in the callbacks (like the existing bleRestartAdvertisingPending)
and do the work in loop() instead.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MgW3EZCfMkGFffseDPwV74
---
 src/ble_init.cpp          |  2 ++
 src/ble_init.h            |  2 ++
 src/esp32_ble_callbacks.h |  5 ++---
 src/main.cpp              | 11 +++++++++++
 4 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/src/ble_init.cpp b/src/ble_init.cpp
index 1c036b4..310ca82 100644
--- a/src/ble_init.cpp
+++ b/src/ble_init.cpp
@@ -137,6 +137,8 @@ void ble_init() {
 
 #ifdef TARGET_ESP32
 volatile bool bleRestartAdvertisingPending = false;
+volatile bool bleConnectMsdUpdatePending = false;
+volatile bool bleDirectWriteCleanupPending = false;
 volatile bool esp32BleNotifySubscribed = false;
 #if defined(CONFIG_BLUEDROID_ENABLED)
 static BLE2902* s_bleNotifyCccd = nullptr;
diff --git a/src/ble_init.h b/src/ble_init.h
index 2ad8d93..f929184 100644
--- a/src/ble_init.h
+++ b/src/ble_init.h
@@ -15,6 +15,8 @@ void esp32_restart_ble_advertising(void);
 void esp32_ble_clear_handles(void);
 bool esp32_ble_notify_enabled(void);
 extern volatile bool bleRestartAdvertisingPending;
+extern volatile bool bleConnectMsdUpdatePending;
+extern volatile bool bleDirectWriteCleanupPending;
 extern volatile bool esp32BleNotifySubscribed;
 #endif
 
diff --git a/src/esp32_ble_callbacks.h b/src/esp32_ble_callbacks.h
index 088613a..69e2079 100644
--- a/src/esp32_ble_callbacks.h
+++ b/src/esp32_ble_callbacks.h
@@ -41,7 +41,7 @@ class MyBLEServerCallbacks : public BLEServerCallbacks {
         writeSerial("=== BLE CLIENT CONNECTED (ESP32) ===");
         rebootFlag = 0;
         esp32BleNotifySubscribed = false;
-        updatemsdata();
+        bleConnectMsdUpdatePending = true;
     }
     void onDisconnect(BLEServer* pServer) {
         (void)pServer;
@@ -50,8 +50,7 @@ class MyBLEServerCallbacks : public BLEServerCallbacks {
         if (epdRefreshInProgress) {
             writeSerial("EPD refresh in progress — deferring cleanup/advertising to main loop");
         } else if (directWriteActive) {
-            cleanupDirectWriteState(true);
-            touchResumeAfterEpdRefresh();
+            bleDirectWriteCleanupPending = true;
         }
         bleRestartAdvertisingPending = true;
     }
diff --git a/src/main.cpp b/src/main.cpp
index cb202f8..41b1c22 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -134,6 +134,17 @@ void loop() {
     if (bleRestartAdvertisingPending) {
         esp32_restart_ble_advertising();
     }
+    if (bleConnectMsdUpdatePending) {
+        bleConnectMsdUpdatePending = false;
+        updatemsdata();
+    }
+    if (bleDirectWriteCleanupPending) {
+        bleDirectWriteCleanupPending = false;
+        if (directWriteActive) {
+            cleanupDirectWriteState(true);
+            touchResumeAfterEpdRefresh();
+        }
+    }
     if (directWriteActive && directWriteStartTime > 0) {
         uint32_t directWriteDuration = millis() - directWriteStartTime;
         if (directWriteDuration > 900000UL) {  // 15 minute timeout (upload + refresh window)