Crash in I2S when use ESP_INTR_FLAG_IRAM flag in the driver config (IDFGH-2432)

[phonec]

Environment

• Development Kit: WEMOS LOLIN32 Pro
• Module: ESP32-WROVER chip rev1
• IDF version: v3.3.1
• Operating System: Linux Ubuntu
• Build System: Make
• Power Supply: USB

Problem Description

When adding a flag ESP_INTR_FLAG_IRAM to the .intr_alloc_flags configuration of i2s driver leads to a crash, because at runtime not all of the data from the i2s_intr_handler_default() interrupt handler function can be found in IRAM, although the function itself has such an attribute: IRAM_ATTR.
In particular, the array of pointers I2S[] does not have an IRAM_ATTR attribute and may not be available when the cache is disabled during such an interrupt.

Solving

Adding this attribute to the I2S pointer on line 102: esp-idf/components/driver/i2s.c

102    static IRAM_ATTR i2s_dev_t * I2S [I2S_NUM_MAX] = {&I2S0, &I2S1};

perhaps it should completely solve this problem, at least it works for me.

Steps to repropduce

Just add this flag to the configuration, for example in the esp-idf/examples/ peripherals/i2s/main/i2s_example_main.c

Debug Logs

Guru Meditation Error: Core  0 panic'ed (Cache disabled but cached memory region accessed)
Core 0 register dump:
PC      : 0x4008753c  PS      : 0x00050034  A0      : 0x40083e10  A1      : 0x3ffb0670
...

(gdb) list *0x4008753c
0x4008753c is in i2s_intr_handler_default (/home/ESP32/esp-idf/components/driver/i2s.c:520).
515
516         portBASE_TYPE high_priority_task_awoken = 0;
517
518         lldesc_t *finish_desc;
519
520         if (i2s_reg->int_st.out_dscr_err || i2s_reg->int_st.in_dscr_err) {
521             ESP_EARLY_LOGE(I2S_TAG, "dma error, interrupt status: 0x%08x", i2s_reg->int_st.val);
522             if (p_i2s->i2s_queue) {
523                 i2s_event.type = I2S_EVENT_DMA_ERROR;
524                 if (xQueueIsQueueFullFromISR(p_i2s->i2s_queue)) {

[xiongyumail]

@phonec

Thanks for the problem you found, it may be better to use DRAM_ATTR. We will merge the changes into the corresponding branches later.

[phonec]

Great. The placement of the I2S interrupt handler in IRAM is necessary to avoid sound distortion during other long-term SPI FLASH operations.

[phonec]

it would be nice to see it also in the 3.3.x

[ctag-fh-kiel]

I have similar issues. The fix is great, but I haven't been able to run my external codec (WM8731) glitch free when reading a file from spiffs flash and serving the file's content with the http server...
Played with the i2s buffers -> no success, played with the i2s INTR flags --> no success
Any advice is much appreciated. WM8731 running at 44.1kHz...

[Alvin1Zhang]

@phonec Thanks for reporting and updates. We have back ported the fixes to IDF v3.3 and is now under internal review, would update once the fix is available on GitHub. Thanks.

[ctag-fh-kiel]

My issue was in fact related to the http server core id. I configured the httpd to use core 0 and i2s core 1. It was unrelated to flash access.

[Alvin1Zhang]

@phonec @ctag-fh-kiel The issue has been fixed and fix available on GitHub. Please help try if the issue still happens, feel free to reopen if the issue persists. Thanks.