How do I know if DMA is working?

[kchudoba]

I have a GUITION device (ESP32-4848s040) (a 480x480 display powered by ESP32S3).
I got it to work with LGFX and LVGL v9 but I'm not sure if I am really using DMA.
On the LVGL music player demo I'm getting 10FPS which is not great.
Is there a way to check if I'm actually using DMA? What else could I be missing?

Here's the LVGL demo code

#include <lvgl.h>

#include <esp_heap_caps.h>
#include <LovyanGFX.hpp>

#include "LGFX_ESP32S3_RGB_Guiton.h"


#include <demos/lv_demos.h>

/*Set to your screen resolution and rotation*/
#define TFT_HOR_RES 480
#define TFT_VER_RES 480
#define TFT_ROTATION LV_DISPLAY_ROTATION_0

/*LVGL draw into this buffer, 1/10 screen size usually works well. The size is in bytes*/
#define DRAW_BUF_SIZE (TFT_HOR_RES * TFT_VER_RES / 10 * (LV_COLOR_DEPTH / 8))

lv_color_t *disp_draw_buf;
lv_color_t *disp_draw_buf1;


LGFX gfx;

#if LV_USE_LOG != 0
void my_print(lv_log_level_t level, const char *buf) {
  LV_UNUSED(level);
  Serial.println(buf);
  Serial.flush();
}
#endif

/* LVGL calls it when a rendered image needs to copied to the display*/
void my_disp_flush(lv_display_t *disp, const lv_area_t *area, unsigned char *color_p)  //uint8_t * px_map)
{
  //Serial.println("my disp flush" );

  if (gfx.getStartCount() == 0) {  // Processing if not yet started
    gfx.startWrite();
  }
  gfx.pushImageDMA(area->x1, area->y1, area->x2 - area->x1 + 1, area->y2 - area->y1 + 1, (lgfx::rgb565_t *)color_p);
  while (gfx.dmaBusy()) {
    //delay(1);  // Allow other tasks to run
    Serial.print("DMA ");
  }
  /*Call it to tell LVGL you are ready*/
  //delay(100);
  lv_display_flush_ready(disp);
}

/*Read the touchpad*/
void my_touchpad_read(lv_indev_t *indev, lv_indev_data_t *data) {
  uint16_t touchX, touchY;

  data->state = LV_INDEV_STATE_RELEASED;

  if (gfx.getTouch(&touchX, &touchY)) {
    data->state = LV_INDEV_STATE_PRESSED;

    /*Set the coordinates*/
    data->point.x = touchX;
    data->point.y = touchY;
  }
}

/*use Arduinos millis() as tick source*/
static uint32_t my_tick(void) {
  return millis();
}

void setup() {
  Serial.begin(115200);


  //disp_draw_buf = (lv_color_t*)heap_caps_malloc(DRAW_BUF_SIZE, MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT);
  disp_draw_buf = (lv_color_t *)heap_caps_malloc(DRAW_BUF_SIZE, MALLOC_CAP_DMA | MALLOC_CAP_8BIT);
  disp_draw_buf1 = (lv_color_t *)heap_caps_malloc(DRAW_BUF_SIZE, MALLOC_CAP_DMA | MALLOC_CAP_8BIT);

  if (!disp_draw_buf) {
    // remove MALLOC_CAP_INTERNAL flag try again
    disp_draw_buf = (lv_color_t *)heap_caps_malloc(DRAW_BUF_SIZE, MALLOC_CAP_8BIT);
    disp_draw_buf1 = (lv_color_t *)heap_caps_malloc(DRAW_BUF_SIZE, MALLOC_CAP_8BIT);
    Serial.println("DMA buffer alloc failed");
  } else {
    Serial.println("DMA buffer alloc successful");
  }

  gfx.init();


  String LVGL_Arduino = "Hello Arduino! ";
  LVGL_Arduino += String('V') + lv_version_major() + "." + lv_version_minor() + "." + lv_version_patch();


  Serial.println(LVGL_Arduino);

  lv_init();

  /*Set a tick source so that LVGL will know how much time elapsed. */
  lv_tick_set_cb(my_tick);

  /* register print function for debugging */
#if LV_USE_LOG != 0
  lv_log_register_print_cb(my_print);
#endif
  Serial.println("before disp");

  lv_display_t *disp;

  /*Else create a display yourself*/
  disp = lv_display_create(TFT_HOR_RES, TFT_VER_RES);
  Serial.println(" disp created, setting flush cb next");

  lv_display_set_flush_cb(disp, my_disp_flush);
  Serial.println(" cb set created, setting buffers next");

  lv_display_set_buffers(disp, disp_draw_buf, disp_draw_buf1, DRAW_BUF_SIZE, LV_DISPLAY_RENDER_MODE_PARTIAL);

  Serial.println("disp buffers set");

  /*Initialize the (dummy) input device driver*/
  lv_indev_t *indev = lv_indev_create();
  lv_indev_set_type(indev, LV_INDEV_TYPE_POINTER); /*Touchpad should have POINTER type*/
  lv_indev_set_read_cb(indev, my_touchpad_read);

  /* Create a simple label
     * ---------------------
     lv_obj_t *label = lv_label_create( lv_screen_active() );
     lv_label_set_text( label, "Hello Arduino, I'm LVGL!" );
     lv_obj_align( label, LV_ALIGN_CENTER, 0, 0 );

     * Try an example. See all the examples
     *  - Online: https://docs.lvgl.io/master/examples.html
     *  - Source codes: https://github.com/lvgl/lvgl/tree/master/examples
     * ----------------------------------------------------------------

     lv_example_btn_1();

     * Or try out a demo. Don't forget to enable the demos in lv_conf.h. E.g. LV_USE_DEMO_WIDGETS
     * -------------------------------------------------------------------------------------------

     
     */
  lv_demo_music();
  // Serial.println( "before drawing label" );

  // lv_obj_t *label = lv_label_create( lv_screen_active() );
  // lv_label_set_text( label, "Hello Arduino, I'm LVGL!" );
  // lv_obj_align( label, LV_ALIGN_CENTER, 0, 0 );

  Serial.println("Setup done");
}

void loop() {
  lv_timer_handler(); /* let the GUI do its work */
  delay(1);           /* let this time pass */
}

[kchudoba]

Hi @tobozo, could I kindly ask you to have a look at my question?

[tobozo]

I've read the question, and since I don't really understand how DMA works all I can answer is that it should be faster than without DMA.