Linker error 'IRAM0 segment data does not fit'

[matthias-bs]

Board

ESP32 Dev Module

Device Description

WaveShare E-Paper ESP32 Driver Board

Hardware Configuration

not relevant

Version

v3.1.2

IDE Name

Arduino IDE

Operating System

Linux

Flash frequency

80 MHz

PSRAM enabled

no

Upload speed

115200

Description

Compiling works of without any errors using esp32:esp32@3.0.7, but fails with a iram0_0_seg overflow linker error using esp32:esp32@3.1.0 or later.

The library versions remain unchanged in both cases.

Sketch

Waveshare_7_5_T7_Sensors.ino

Debug Message

/home/mp/.arduino15/packages/esp32/tools/esp-x32/2405/bin/../lib/gcc/xtensa-esp-elf/13.2.0/../../../../xtensa-esp-elf/bin/ld: /tmp/arduino/sketches/EF8ECBDC67641FB780F7048771789765/Waveshare_7_5_T7_Sensors.ino.elf section `.iram0.text' will not fit in region `iram0_0_seg'
/home/mp/.arduino15/packages/esp32/tools/esp-x32/2405/bin/../lib/gcc/xtensa-esp-elf/13.2.0/../../../../xtensa-esp-elf/bin/ld: IRAM0 segment data does not fit.
/home/mp/.arduino15/packages/esp32/tools/esp-x32/2405/bin/../lib/gcc/xtensa-esp-elf/13.2.0/../../../../xtensa-esp-elf/bin/ld: region `iram0_0_seg' overflowed by 1520 bytes
collect2: error: ld returned 1 exit status

Error during build: exit status 1

Other Steps to Reproduce

See CI for reference:

• https://github.com/matthias-bs/ESP32-e-Paper-Weather-Display/actions/runs/12346840604 (ok)
  arduino-cli Version: 1.1.1
  esp32:esp32@3.0.7 (idf-release_v5.1)

• https://github.com/matthias-bs/ESP32-e-Paper-Weather-Display/actions/runs/13746757534 (failed)
  arduino-cli Version: 1.2.0
  esp32:esp32@3.1.3 (idf-release_v5.3)

The solution proposed in #10756 was not applicable in my case, because I was already using ARDUINO_ISR_ATTR.

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.

[Jason2866]

Not a bug. The newer Arduino core needs a little more resources. Looks like this slightly difference is too much to fit in IRAM. Your code needs to be optimized to use less IRAM. Or stay at the older core.

[me-no-dev]

We are not using IRAM in Arduino and have turned many IRAM optimizations OFF in IDF, but that does not mean that IDF itself has not added IRAM functions itself. That and the fact that one of the external libraries in your project are also adding IRAM functions is what usually leads to this.

[matthias-bs]

I had a look at https://docs.espressif.com/projects/esp-idf/en/v5.4/esp32/api-guides/performance/ram-usage.html and tried a few tweaks in build_opt.h

-DCONFIG_FREERTOS_PLACE_FUNCTIONS_INTO_FLASH
-DCONFIG_HAL_DEFAULT_ASSERTION_LEVEL
-DCONFIG_BT_NIMBLE_ROLE_OBSERVER_DISABLED
-DCONFIG_BT_NIMBLE_ROLE_PERIPHERAL_DISABLED
-DCONFIG_BT_NIMBLE_MAX_BONDS=1
-DCONFIG_BT_NIMBLE_CRYPTO_STACK_MBEDTLS=1

-- unfortunately without luck.

Any other hints?

[me-no-dev]

It can't work like that, because ESP-IDF is already pre-compiled. If you want to test the flags, you can try building custom libs with the lib-builder that have those on. https://docs.espressif.com/projects/arduino-esp32/en/latest/lib_builder.html

[matthias-bs]

@me-no-dev Ah, no, thanks! I'm looking for a solution which still allows the average Arduino IDE user to build the sketch.

[me-no-dev]

If your tests pass, we could look into enabling the flags for ESP32 in our default Arduino libs

[me-no-dev]

AMF only the first two are relevant at the moment. We do not use NimBLE yet :)

[matthias-bs]

That means NimBLE is compiled with the sketch and I might try to disable unused parts by customizing its configuration (https://github.com/h2zero/NimBLE-Arduino/blob/master/src/nimconfig.h)?