HardwareSerial::availableForWrite still return 128 after HardwareSerial::setTxBufferSize

[imwhocodes]

Board

ESP32 Dev Module

Device Description

Custom PCB

Hardware Configuration

A lot of stuff

Version

latest master (checkout manually)

IDE Name

Platformio

Operating System

Macos

Flash frequency

80

PSRAM enabled

no

Upload speed

115200

Description

I'm trying to use the new feature of v2.0.3

After setting TX buffer size with HardwareSerial::setTxBufferSize the function HardwareSerial::availableForWrite still always return 128 keeping track only of the free space in the TxFIFO without accounting of the newly allocated buffer for transmission

Sketch

#define NO_GLOBAL_SERIAL
#include <Arduino.h>

HardwareSerial SerialTest{1};

void setup(){
  SerialTest.setRxBufferSize(4096);
  SerialTest.setTxBufferSize(4096);
  SerialTest.begin(9600);
}

void loop() {
  log_e("availableForWrite:\t%d\n", SerialTest.availableForWrite());
}

Debug Message

availableForWrite: 128
availableForWrite: 128
availableForWrite: 128
availableForWrite: 128
availableForWrite: 128
availableForWrite: 128
....

Other Steps to Reproduce

No response

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

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

[SuGlider]

@imwhocodes - Issue confirmed. Along the changes this fuction was left behind.
availableForWrite() only looks into the FIFO space. It has to be updated/fixed.

Thanks for reporting. I'll set a PR to fix it.

[SuGlider]

I just looked into the code.... there is a big problem.
IDF has no function to get the left space in TX Ring Buffer associated to setTxBufferSize(size).
The Ring Buffer is created by IDF, but it can't be read, neither accessed.

I'll investigate it further, but it looks like there is no way to fix it at this time.

[imwhocodes]

I opened an issue / feature request on esp-idf, let see what they say

espressif/esp-idf#8932

[imwhocodes]

I opened an issue / feature request on esp-idf, let see what they say

espressif/esp-idf#8932

@SuGlider issue was fixed on esp-idf repo, we need to update Arduino internal code

[SuGlider]

Thanks @imwhocodes
At this time this IDF function has been merged for IDF 5.0.
I've requested a backport to IDF 4.4 in order to allow us to use it within ESP32 Arduino Core.
I'll follow it as well.

[SuGlider]

I think it may be availble for a Arduino Core 2.0.5 (next release).
I'll add the fixes in the Arduino API and post a PR ready for when we have this IDF function in IDF 4.4.

[SuGlider]

It has been backported to 4.4: espressif/esp-idf@dfb75aa
Confirmed to be present in the next Core Release based on PR e193e2a

[SuGlider]

@imwhocodes - PR #6998 shall solve the issue. Thanks for the help!