[v9.2.2] How to LV_USE_STDLIB_MALLOC by PSRAM (ps_malloc) on ESP32?

How-to
1

Description

I want to allocate memory from LV_STDLIB_BUILTIN to use PSRAM with ps_malloc on ESP32. Is this possible, and how can it be done?

Thank you.

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

ESP32, ESP32S3

What LVGL version are you using?

v9.2.2

What do you want to achieve?

use PSRAM with ps_malloc for widgets

2

in your sdkconfig file you need to set

CONFIG_SPIRAM_USE_MALLOC=y

optionally you can use menuconfig to configure the project and you can locate that setting in Component config > ESP PSRAM > CONFIG_SPIRAM > SPI RAM config

3

also I an not sure what ps_malloc is because it is not in the SDK for the ESP32. The memory allocation function for the ESP32 begin with heap_caps_.

4

Thank you for your response.
Currently, I am using the Arduino platform, and PSRAM has been successfully set up using ESP-IDF as you suggested earlier.

Now, I want to use ps_malloc(…) to replace the default LV_STDLIB_MALLOC, which is currently set to LV_STDLIB_BUILDIN. I intend to change it to LV_STDLIB_CUSTOM in lv_conf.h.

However, I am unsure how to configure it when using LV_STDLIB_CUSTOM. Specifically, how should I set ps_malloc(…) to be called as a custom allocation function?

In earlier versions of LVGL, it was possible to replace malloc with an external function like ps_malloc(…). However, in LVGL 9.x, I don’t understand how to configure this for using external malloc ( ps_malloc(…) .

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5

If you open up src/stdlib/builtin/lv_mem_core_builtin.c in lvgl you will see all of the different memory functions. You need to create your own version of all of those functions. Then set LV_USE_STDLIB_MALLOC to LV_STDLIB_CUSTOM make sure in the C course file that contain your versions of the functions that you include src/stdlib/lv_mem.h as that is where the function prototypes are

6

This doesn’t seem reasonable; do I need to implement every function in lv_mem.h?

7

Hi, did you ever manage to resolve this ? I have an ESP32S3 now and can’t succeed using PSRAM in any way. Thanks.

8

for the ESP32 it’s a setting you need to set in the ESP-IDF menuconfig to get the memory to be used.

9

Why not just setup the conf LV_ATTRIBUTE_LARGE_RAM_ARRAY to EXT_RAM_BSS_ATTR in lv_conf.h

In my projects (using esp-idf and cmake) I add this to CMakeLists.txt

add_compile_definitions(CONFIG_LV_ATTRIBUTE_LARGE_RAM_ARRAY=EXT_RAM_BSS_ATTR)

Since the option doesn’t show in menuconfig, it uses LVGL internal memory manager with a static buffer (set size with LV_MEM_SIZE), but the buffer is allocated in the external SPIRAM.

Obviously SPIRAM must be enabled in the project configuration…