esp_lvgl_port: 90/270 degree software rotation issue (BSP-732)

[dmartauz]

Board

custom board with ESP32-P4 with ILI9881C MIPI display

Hardware Description

• custom board with ESP32-P4 (revision 1.3)
• ILI9881C-based LCD

IDE Name

No IDE, just idf.py

Operating System

Windows 10

Description

I am using 800x1280 ILI9881C-based LCD in landscape orientation. Because the controller does not support hardware rotation I am using software implementation.

IDF version: esp-idf-master branch, commit ab149384e12ace1b8e8f7858d52ae47ab8af4563 (latest as of today October 24)
esp_lvgl_port version: 2.6.2
lvgl version: 9.4.0

Simple Hello world screen is rendered correctly with LV_DISPLAY_ROTATION_0 or LV_DISPLAY_ROTATION_180.

However with LV_DISPLAY_ROTATION_90 or LV_DISPLAY_ROTATION_270 I am encountering this issue:

I (3156) LVGL: Starting LVGL task
I (3156) example: Add LCD screen
Guru Meditation Error: Core  0 panic'ed (Load access fault). Exception was unhandled.

--- Stack dump detected
Core  0 register dump:
MEPC    : 0x4fc19f54  RA      : 0x4009c8ae  SP      : 0x4ff3dfd0  GP      : 0x4ff16400
--- 0x4009c8ae: dpi_panel_draw_bitmap at C:/Espressif/frameworks/esp-idf-master/components/esp_lcd/dsi/esp_lcd_panel_dpi.c:542

Sketch

        .io_handle = mipi_dbi_io,
        .panel_handle = mipi_dpi_panel,
        .buffer_size =  EXAMPLE_MIPI_DSI_LCD_V_RES * EXAMPLE_MIPI_DSI_LCD_H_RES / 20,
        .double_buffer = false,
        .hres = EXAMPLE_MIPI_DSI_LCD_H_RES,
        .vres = EXAMPLE_MIPI_DSI_LCD_V_RES,
        .monochrome = false,
        .color_format = LV_COLOR_FORMAT_RGB565,
        .rotation = {
            .swap_xy = false,
            .mirror_x = false,
            .mirror_y = false,
        },
        .flags = {
            .buff_dma = true,
            .buff_spiram = false,
            .sw_rotate = true,
            .swap_bytes = false,
            .full_refresh = false,
            .direct_mode = false,
        }
    };

    const lvgl_port_display_dsi_cfg_t disp_dsi_cfg;

    lvgl_display = lvgl_port_add_disp_dsi(&disp_cfg, &disp_dsi_cfg);
    lv_display_set_rotation(lvgl_display, LV_DISPLAY_ROTATION_90);

[github-actions]

Hi @dmartauz! Please be aware that (1) the following suggestions are generated by a bot and haven't been fact-checked by Espressif Systems, (2) burning eFuses and enabling security features are irreversible operations and can damage your ESP32 device. We hope that this message will help you until an Espressif Engineer looks at your issue.

---

Thank you for the detailed report. Based on your description and the provided configuration, here are some key points and recommendations regarding software rotation with esp_lvgl_port on ESP32-P4 and MIPI-DSI displays:

1. Software Rotation Support and Limitations

• Software rotation (sw_rotate = true) is supported by esp_lvgl_port and is required when the display controller (like ILI9881C) does not support hardware rotation.
• When using software rotation, you must not enable direct_mode or full_refresh in the driver, as these modes are incompatible with software rotation and can cause unexpected behavior or failures. Your configuration correctly sets both to false [esp_lvgl_port Usage].

2. RAM Usage and Buffer Size

• Software rotation consumes more RAM, as the rotated frame must be rendered in memory before being sent to the display. Ensure your buffer size is sufficient for the rotated resolution, especially for high-resolution displays like 800x1280. The buffer size in your config appears small (/20), which may not be enough for smooth operation or may cause memory access issues [esp_lvgl_port Usage].

3. PPA Acceleration

• On ESP32-P4, software rotation uses the PPA (Pixel Processing Accelerator) if available, which should improve performance. However, there have been known issues with PPA freezes or faults under certain conditions, especially with heavy workloads or specific buffer configurations [esp-iot-solution MIPI-DSI Avoid Tearing Example].

4. Known Issues and Patches

• There is a known issue with PPA freezes in rotation/anti-tearing scenarios, which can cause faults similar to what you are experiencing. The recommended solution is to apply a patch to ESP-IDF (for v5.5, but may be relevant for master branch as well) that fixes a register configuration in the PPA SRM path. See the instructions and patch here: esp-iot-solution MIPI-DSI Avoid Tearing Example.

5. Mutex Protection

• All LVGL API calls must be protected by a mutex, especially when using custom tasks or multiple threads, to avoid race conditions and memory access faults. Ensure that your code follows this pattern around all LVGL calls [esp-iot-solution MIPI-DSI Avoid Tearing Example].

6. Diagonal Tearing and SW Rotation

• For SPI screens, it is recommended to enable the LVGL sw_rotate flag for software rotation. However, this function conflicts with full_refresh and direct_mode, so do not use them together [ESP FAQ: Diagonal Tearing].

---

Recommended Actions

1. Increase Buffer Size:
   Try increasing the buffer_size in your disp_cfg to at least one full screen (or more, if memory allows), especially for high-resolution displays and software rotation.

2. Apply the PPA Patch:
   If you are using a recent ESP-IDF master, check if the PPA freeze patch has been merged. If not, apply the patch as described in the esp-iot-solution example.

3. Mutex Protection:
   Ensure all LVGL API calls are protected by a mutex, especially in multi-threaded environments.

4. Check for Updates:
   Make sure you are using the latest versions of esp_lvgl_port and ESP-IDF, as there have been recent fixes related to rotation and buffer handling [esp_lvgl_port Changelog].

---

If the issue persists after these steps, please provide additional details such as the full stack trace and your memory configuration. This will help further diagnose whether the problem is due to buffer size, a PPA bug, or another cause.

---

References:

• esp_lvgl_port Usage: Rotating screen
• esp-iot-solution MIPI-DSI Avoid Tearing Example
• esp_lvgl_port Changelog
• ESP FAQ: Diagonal Tearing

[dmartauz]

Here is minimal example.
Update lv_display_set_rotation(lvgl_display, LV_DISPLAY_ROTATION_0); on line 397 in lvgl_ui_task.c to 90 or 270 and the issue will appear.
20251024_dsi_test.zip