From 1a6be99884651cd2419758faa8c304f8b75ac9c0 Mon Sep 17 00:00:00 2001
From: 0xDEADBEEF <0xde4dbeef@gmail.com>
Date: Tue, 15 Sep 2020 15:22:47 +0200
Subject: [PATCH] add I2C_RX_FIFO_OVF_INT_ST handling to
 i2c_isr_handler_default

Fixes crash on ESP32 when I2C FiFo overflows and interrupt function is unable to handle crash and throws this error:
[E][esp32-hal-i2c.c:1013] i2c_isr_handler_default(): unknown int=4
---
 cores/esp32/esp32-hal-i2c.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/cores/esp32/esp32-hal-i2c.c b/cores/esp32/esp32-hal-i2c.c
index d85919cfdb3..d50ce4cc029 100644
--- a/cores/esp32/esp32-hal-i2c.c
+++ b/cores/esp32/esp32-hal-i2c.c
@@ -945,6 +945,14 @@ static void IRAM_ATTR i2c_isr_handler_default(void* arg)
             activeInt &=~I2C_RXFIFO_FULL_INT_ST;
         }
 
+        if(activeInt & I2C_RXFIFO_OVF_INT_ST) {
+            emptyRxFifo(p_i2c);
+            p_i2c->dev->int_clr.rx_fifo_full=1;
+            p_i2c->dev->int_ena.rx_fifo_full=1; //why?
+
+            activeInt &=~I2C_RXFIFO_OVF_INT_ST;
+        }
+
         if (activeInt & I2C_ACK_ERR_INT_ST_M) {//fatal error, abort i2c service
             if (p_i2c->mode == I2C_MASTER) {
                 i2c_update_error_byte_cnt(p_i2c); // calc which byte caused ack Error, check if address or data