lcd.dsi.dpi: dpi_panel_draw_bitmap(530): previous draw operation is not finished

[Westcott1]

Board ESP32P4 Guition JC8012P4A1 MIPI-DSI
Arduino IDE 2.3.5
Expressiv esp32 3.2.1
ESP-IDF 5.4.2
LVGL 9.3.0
ESP32_Display_Panel 1.0.3

This is my first attempt at using ESP32_Display_Panel , up 'til now I've used Lovyan_GFX or Arduino_GFX.
Yes I know that neither this board nor LVGL9 is officially supported yet.
However all of the graphics renders correctly.
It is only when updating label text several times a second that the error occurs.
Many updates don't have an error.
lcd.dsi.dpi: dpi_panel_draw_bitmap(530): previous draw operation is not finished
Here is the LVGL flush function -

void LvDispFlush(lv_display_t *disp, const lv_area_t *area, uint8_t *color_map) {
const int offsetx1 = area->x1;
const int offsetx2 = area->x2;
const int offsety1 = area->y1;
const int offsety2 = area->y2;
Serial.println("draw_bitmap"); <---------------- The error message is directly after this
lcd.lcd_draw_bitmap(offsetx1, offsety1, offsetx2 + 1, offsety2 + 1, color_map);
// Not needed - handled instead by lv_display_set_flush_wait_cb()
// lv_display_flush_ready(disp);
}

I've not been able to find this error message anywhere in the src.
Nor can I find the function esp_lcd_panel_draw_bitmap

[Lzw655]

Hi @Westcott1,

The error message is located in the ESP-IDF driver code.

The MIPI-DSI interface usually transfers data in the draw_bitmap() function using the DMA method. So even if the draw_bitmap() function has completed, the data is still being transferred. If you call draw_bitmap() again at this time, this problem will be triggered. Therefore, you need to wait for the previous transfer to complete before doing so.

[Westcott1]

Hi Lzw655,
Thanks for the explanation and link to the code.
I'd guessed that is what the reason was, and where the code might be, but still couldn't find it.
It seems that this check is only in the dpi panel code, so no-one else is bothered by it - yet.
Do you have any idea cow I can test to see if I need to wait for the previous transfer to complete?
The semaphore is a member of struct esp_lcd_dpi_panel_t

[Lzw655]

Hi @Westcott1,

If you are using the drawBitmap() function in this library, it provides an interface attachDrawBitmapFinishCallback() to register a callback function. The registered callback function will be called when the data transfer is completed. Refer to the example.

[Westcott1]

Hi Lzw655,
Thanks for that,
Unfortunately I'm not using drawBitmap.
I am in fact using someone's custom setup for a jd9365 panel + ESP32-P4.
On Arduino and LVGL9
Perhaps I'll wait until it's all supported officially.
My app works really well, apart from dropping a few text updates.