From 054e6b3d56b51ddf4de2df0df09be7253f1cbab9 Mon Sep 17 00:00:00 2001
From: Rodrigo Garcia <rodrigo.garcia@espressif.com>
Date: Mon, 8 Aug 2022 10:29:09 -0300
Subject: [PATCH] Fixes HardwareSerial::availableForWrite + setTxBufferSize
 (#6998)

---
 cores/esp32/esp32-hal-uart.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/cores/esp32/esp32-hal-uart.c b/cores/esp32/esp32-hal-uart.c
index 09a68b83d..0b445cbc4 100644
--- a/cores/esp32/esp32-hal-uart.c
+++ b/cores/esp32/esp32-hal-uart.c
@@ -238,6 +238,10 @@ uint32_t uartAvailableForWrite(uart_t* uart)
     }
     UART_MUTEX_LOCK();
     uint32_t available =  uart_ll_get_txfifo_len(UART_LL_GET_HW(uart->num));  
+    size_t txRingBufferAvailable = 0;
+    if (ESP_OK == uart_get_tx_buffer_free_size(uart->num, &txRingBufferAvailable)) {
+        available += txRingBufferAvailable; 
+    }
     UART_MUTEX_UNLOCK();
     return available;
 }