LV_timer_handler() stuck, Flush never called

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1

Description

my code is getting stuck on lv_timer_handler(); and my flush callback is never getting called. There is nothing rendering on my display. I was able to get everything successfully running yesterday, but after a small change to my code everything broke, even after undoing the change ;-;

What MCU/Processor/Board and compiler are you using?

Esp32 Feather V2
Waveshape 7.5in B/W display
Arduino Ide
Currently tested with LVGL 9.2.2, 9.2.1

What do you want to achieve?

I want my code to call my_disp_flush() so that my UI will be rendered

What have you tried so far?

I don’t understand why this issue is happening, I’ve added a bunch of error checking so I have narrowed down where my issue is occuring:

Code to reproduce

Add the relevant code snippets here.

The code block(s) should be between ```c and ``` tags:

/* Display Flush */
void my_disp_flush(lv_display_t* disp, const lv_area_t* area, uint8_t* color_p) {
  Serial.println("Flush Called");  // Debugging Purposes

  // Define dimensions of area being updated
  uint32_t width = lv_area_get_width(area);
  uint32_t height = lv_area_get_height(area);


  uint16_t* color_buf16 = (uint16_t*)color_p;

  // Define area being update
  display.setPartialWindow(area->x1, area->y1, width, height);

  // For epaper "pages" are horizontal strips that are updated sequentially to save memory/space
  display.firstPage();
  do {
    for (uint32_t y = 0; y < height; y++) {
      for (uint32_t x = 0; x < width; x++) {
        uint16_t color = color_buf16[y * width + x];
        uint8_t gray = ((color & 0xF800) >> 8) |  // Red contribution
                       ((color & 0x07E0) >> 3) |  // Green contribution
                       ((color & 0x001F) << 3);   // Blue contribution

        display.drawPixel(
          area->x1 + x,
          area->y1 + y,
          gray < 128 ? GxEPD_BLACK : GxEPD_WHITE);
      }
    }
  } while (display.nextPage());  // Loops until all pages are displayed

  // Small delay to ensure e-paper has time to update
  delay(10);

  lv_disp_flush_ready(disp);  // Inform lvgl that update is complete
}

/* LVGL setup */
  // Initialize LVGL
  lv_init();
  Serial.print("Lvgl Init");

  // Tick callback
  lv_tick_get_cb_t tick_cb = my_tick_get_cb;
  lv_tick_set_cb(tick_cb);

  // Initialize Display
  display.init(115200);
  display.setRotation(0);  // Landcape Mode
  display.setPartialWindow(0, 0, screenWidth, screenHeight);

  // Clear display with proper full refresh
  display.setFullWindow();
  display.firstPage();
  do {
    display.fillScreen(GxEPD_WHITE);
  } while (display.nextPage());



  // Create LVGL display
  lv_display_t* disp = lv_display_create(screenWidth, screenHeight);
  if (!disp) {
    Serial.println("LVGL display creation failed!");
    while (1)
      ;
  }
  Serial.println("LVGL display created");

    // Allocate display buffer
  const int bufferHeight = screenHeight;  // Reduce buffer size b/c dram is overflowing -> mem allocated reduced testing without reducing buffersize, was originally screenHeight
  static lv_color_t* disp_buf = (lv_color_t*)malloc(screenWidth * bufferHeight * sizeof(lv_color_t));
  if (!disp_buf) {
    Serial.println("Display buffer allocation failed!");
    while (1);
  }

  Serial.println("Buffer allocated");

  // Configure display
  lv_display_set_buffers(disp, disp_buf, NULL,
                         screenWidth * bufferHeight * sizeof(lv_color_t),
                         LV_DISPLAY_RENDER_MODE_PARTIAL);

  Serial.println("Display Buffers set");

  lv_display_set_flush_cb(disp, my_disp_flush);
  Serial.println("Flush callback set");

  lv_display_set_render_mode(disp, LV_DISPLAY_RENDER_MODE_PARTIAL);

  Serial.println("Initing UI");

  // Initialize UI
  ui_init();
  lv_scr_load(ui_Screen1);

  delay(100); // brief pause for everything to catch up

  // Initialize lastMillis
  lastMillis = millis();


  // Update display with an initial forecast and stuff
  updateDisplay();
  updateTime();
  Serial.println("Setup Done");
}

void loop() {
  
  if (loopCount < 5) {
    Serial.println("Looping");
    loopCount++;
  }

  // lv_display_t* disp = lv_display_get_default();
  // if (disp && !lv_display_is_rendering(disp)) {
  //   Serial.println("Triggering refresh");
  //   lv_refr_now(disp);
  // }
  
  Serial.println("Before timer handler");
  lv_timer_handler();
  Serial.println("After timer handler"); // CODE NEVER REACHES THIS LINE

Screenshot and/or video

If possible, add screenshots and/or videos about the current state.

2

primary you dont show this code = most important code.
secondary why dont show your logged info?
and delay(10) in flush isnt right method. Lvconf define speed for refresh .

3

Hi Marian, you are an absolute lifesaver. I turned on logging and identified the issue. I exceeded my memory by about 1k bytes. I fixed this by going into LVconf and giving lvgl a tad bit more memory.

This was causing me so much stress and you actually saved me, my project is due Tomorrow, and I managed to break it after it was already working.