serialport/bindings-cpp/unixRead read error [Error: EAGAIN: resource temporarily unavailable, read]

[semireg]

SerialPort Version

Tested 10-12

Node Version

Electron main

Electron Version

Tested 26-30

Platform

Sonoma 14.14.1 - Darwin Kernel Version 23.4.0 macOS

Architecture

ARM

Hardware or chipset of serialport

FTDI FT232R USB UART (PID: 0x6001)

What steps will reproduce the bug?

I have a weight scale that responds to a simple "W\r\n". This works fine using screen /dev/tty.usbserial-AI04V9SR 9600, here's the expected output:

I'm no stranger to USB devices, Electron, native modules, TypeScript, etc. I'm unable to get serialport to work as I'd expect.

What happens?

Here's the output from electron 26.6.9 main when DEBUG=*

  serialport/bindings-cpp list +0ms
  serialport/stream opening path: /dev/tty.usbserial-AI04V9SR +0ms
  serialport/bindings-cpp open +1ms
  serialport/stream _read queueing _read for after open +0ms
  serialport/bindings-cpp/poller Creating poller +0ms
  serialport/stream opened path: /dev/tty.usbserial-AI04V9SR +27ms
  serialport/stream _read reading { start: 0, toRead: 65536 } +0ms
  serialport/bindings-cpp read +27ms
  serialport/bindings-cpp/unixRead Starting read +0ms
10:50:45.861 ›   28 | ScaleManager opening path /dev/tty.usbserial-AI04V9SR
  serialport/bindings-cpp/unixRead read error [Error: EAGAIN: resource temporarily unavailable, read] {
  errno: -35,
  code: 'EAGAIN',
  syscall: 'read'
} +0ms
  serialport/bindings-cpp/unixRead waiting for readable because of code: EAGAIN +0ms
  serialport/bindings-cpp/poller Polling for "readable" +1ms
  serialport/bindings-cpp list +2s
10:50:47.841 ›    3 | ScaleManager write (AI04V9SR at path /dev/tty.usbserial-AI04V9SR): W

  serialport/stream _write 3 bytes of data +2s
  serialport/bindings-cpp write 3 bytes +4ms
  serialport/bindings-cpp/unixWrite Starting write 3 bytes offset 0 bytesToWrite 3 +0ms
...

My calling code is fairly vanilla. I've tried with autoOpen:true/false, with/without a parser. Here's a code sample:

            const port = new SerialPort({ path, baudRate: 9600, autoOpen: false });
            port.open((openError) => {
              log.info(`ScaleManager opening path ${path}`);
              if (openError) {
                log.error(`ScaleManager portInfo:${JSON.stringify(portInfo)} openError:${openError}`);
                return;
              }
              deviceWrapper.ready = true;
            });

            const newParser = port.pipe(new InterByteTimeoutParser({ interval: 50 }));
            newParser.on('data', (data: Buffer) => {
              log.info('Data:', data);
            });

My writing looks like:

port.write(Buffer.from('W\r\n'), 'utf-8', (writeError) => {
                  if (writeError) {
                    log.error(`ScaleManager writeError:${writeError}`);
                    port.close();
                  }
                });

My goal is to keep targeting Electron 26 due to macOS 10.13/10.14, along with other native module compatibility.

Here's the DEBUG repl using node v18.17.1.

% DEBUG=serialport* npx @serialport/repl /dev/tty.usbserial-AI04V9SR
  serialport/bindings-cpp loading DarwinBinding +0ms
DEBUG=serialport* # enable debugging with DEBUG=serialport*
port = SerialPort({ path: "/dev/tty.usbserial-AI04V9SR", baudRate: 9600, autoOpen: false })
globals { SerialPort, SerialPortMock, path, port }
> port.open()
  serialport/stream opening path: /dev/tty.usbserial-AI04V9SR +0ms
  serialport/bindings-cpp open +0ms
undefined
>   serialport/bindings-cpp/poller Creating poller +0ms
  serialport/stream opened path: /dev/tty.usbserial-AI04V9SR +30ms

undefined
> port.write('W\r\n');
  serialport/stream _write 3 bytes of data +7s
  serialport/bindings-cpp write 3 bytes +7s
  serialport/bindings-cpp/unixWrite Starting write 3 bytes offset 0 bytesToWrite 3 +0ms
true
>   serialport/bindings-cpp/unixWrite write returned: wrote 3 bytes +1ms
  serialport/bindings-cpp/unixWrite Finished writing 3 bytes +0ms
  serialport/stream binding.write write finished +2ms

undefined
> port.read()
  serialport/stream _read reading { start: 0, toRead: 65536 } +3s
  serialport/bindings-cpp read +3s
  serialport/bindings-cpp/unixRead Starting read +0ms
null
>   serialport/bindings-cpp/unixRead read error [Error: EAGAIN: resource temporarily unavailable, read] {
  errno: -35,
  code: 'EAGAIN',
  syscall: 'read'
} +1ms
  serialport/bindings-cpp/unixRead waiting for readable because of code: EAGAIN +0ms
  serialport/bindings-cpp/poller Polling for "readable" +11s

undefined

Immediately after this I can type screen /dev/tty.usbserial-AI04V9SR 9600 and press W and receive a response from the scale.

Oh, and here's the stty/permission settings.

% ls -lah /dev/tty.usbserial-AI04V9SR    
crw-rw-rw-  1 root  wheel  0x9000002 Apr 19 11:07 /dev/tty.usbserial-AI04V9SR

% stty -a -f /dev/tty.usbserial-AI04V9SR
speed 9600 baud; 0 rows; 0 columns;
lflags: -icanon -isig -iexten -echo -echoe -echok -echoke -echonl
	-echoctl -echoprt -altwerase -noflsh -tostop -flusho -pendin
	-nokerninfo -extproc
iflags: -istrip -icrnl -inlcr -igncr -ixon -ixoff -ixany -imaxbel -iutf8
	-ignbrk -brkint -inpck -ignpar -parmrk
oflags: -opost -onlcr -oxtabs -onocr -onlret
cflags: cread cs8 -parenb -parodd hupcl -clocal -cstopb -crtscts -dsrflow
	-dtrflow -mdmbuf
cchars: discard = ^O; dsusp = ^Y; eof = ^D; eol = <undef>;
	eol2 = <undef>; erase = ^?; intr = ^C; kill = ^U; lnext = ^V;
	min = 1; quit = ^\; reprint = ^R; start = ^Q; status = ^T;
	stop = ^S; susp = ^Z; time = 0; werase = ^W;

What should have happened?

I'd just like to see the output of the weight scale.

Additional information

I've unplug/replugged the USB device multiple times to ensure it's a clean/fresh interface. No difference, unfortunately.

[thepasto]

I have the same issue, with similar scenario. I'm running archlinux with electron 26.2.1 serialport v12
I can successfully read from serial when running in debug mode via phpstrom debug, but it fails to run in development or production mode.

dev mode output:

serialport/stream opening path: /dev/ttyACM0 +0ms
serialport/bindings-cpp open +2s
serialport/stream _read queueing _read for after open +2ms
serialport/bindings-cpp/poller Creating poller +0ms
serialport/stream opened path: /dev/ttyACM0 +187ms
serialport/stream _write 18 bytes of data +0ms
serialport/bindings-cpp write 18 bytes +189ms
serialport/bindings-cpp/unixWrite Starting write 18 bytes offset 0 bytesToWrite 18 +0ms
serialport/stream _read reading { start: 0, toRead: 65536 } +0ms
serialport/bindings-cpp read +1ms
serialport/bindings-cpp/unixRead Starting read +0ms
serialport/bindings-cpp/unixWrite write returned: wrote 18 bytes +1ms
serialport/bindings-cpp/unixWrite Finished writing 18 bytes +0ms
serialport/stream binding.write write finished +1ms
message written
serialport/bindings-cpp/unixRead read error [Error: EAGAIN: resource temporarily unavailable, read] {
errno: -11,
code: 'EAGAIN',
syscall: 'read'
} +0ms
serialport/bindings-cpp/unixRead waiting for readable because of code: EAGAIN +0ms
serialport/bindings-cpp/poller Polling for "readable" +3ms

With debug enabled

  serialport/stream opening path: /dev/ttyACM0 +0ms
  serialport/bindings-cpp open +6s
  serialport/stream _read queueing _read for after open +2s
  serialport/bindings-cpp/poller Creating poller +0ms
  serialport/stream opened path: /dev/ttyACM0 +1ms
  serialport/stream _write 18 bytes of data +0ms
  serialport/bindings-cpp write 18 bytes +2s
  serialport/bindings-cpp/unixWrite Starting write 18 bytes offset 0 bytesToWrite 18 +0ms
  serialport/stream _read reading { start: 0, toRead: 65536 } +1ms
  serialport/bindings-cpp read +0ms
  serialport/bindings-cpp/unixRead Starting read +0ms
  serialport/bindings-cpp/unixWrite write returned: wrote 18 bytes +3ms
  serialport/bindings-cpp/unixWrite Finished writing 18 bytes +1ms
  serialport/stream binding.write write finished +4ms
  serialport/bindings-cpp/unixRead read error [Error: EAGAIN: resource temporarily unavailable, read] {
  errno: -11,
  code: 'EAGAIN',
  syscall: 'read'
} +1s
  serialport/bindings-cpp/unixRead waiting for readable because of code: EAGAIN +1ms
  serialport/bindings-cpp/poller Polling for "readable" +1s
  serialport/bindings-cpp/poller received "readable" +2ms
  serialport/bindings-cpp/unixRead Starting read +3ms
  serialport/bindings-cpp/unixRead Finished read 29 bytes +0ms
  serialport/stream binding.read finished { bytesRead: 29 } +1s
  serialport/stream _read reading { start: 29, toRead: 65507 } +8s
  serialport/bindings-cpp read +10s
  serialport/bindings-cpp/unixRead Starting read +8s
  serialport/stream #close +6s
  serialport/bindings-cpp close +6s
  serialport/bindings-cpp/poller Stopping poller +14s
  serialport/bindings-cpp/poller Destroying poller +0ms
Data2: <Buffer 52 65 63 65 69 76 65 64 3a 20 50 52 4f 56 41 20 50 52 4f 56 41 20 50 52 4f 56 41 0d 0a>
Readable Buffer: <Buffer 52 65 63 65 69 76 65 64 3a 20 50 52 4f 56 41 20 50 52 4f 56 41 20 50 52 4f 56 41 0d 0a>
  serialport/bindings-cpp/unixRead read error [Error: EAGAIN: resource temporarily unavailable, read] {
  errno: -11,
  code: 'EAGAIN',
  syscall: 'read'
} +6s
  serialport/stream binding.read error BindingsError: Port is not open
    at unixRead (/home/thepasto/workspace/IRIDE/electron-iwcassa2/release/app/node_modules/@serialport/bindings-cpp/dist/unix-read.js:38:23) {
  canceled: true
} +7ms
  serialport/stream _read queueing _read for after open +0ms
  serialport/stream binding.close finished +56ms

Any clue?
If you need more, just ask.

Thanks

[erhard]

Same problem MAC M1....
const port = new SerialPort({
path: '/dev/tty.SLAB_USBtoUART7',
baudRate: 38400,
stopBits: 1,
})
console.log(port.binding)
port.binding gives undefined.

checking console.log(port) : the buffer is full but not readable with port.on("data", (data)=>console.log(data))

Here the buffer :
_pool: <Buffer 76 37 00 14 ea 91 06 10 e2 03 02 aa e2 03 02 aa 10 00 80 d2 4a 01 14 cb ea ce 1f b8 0a 10 8a d2 0a 70 a4 f2 2a 00 c0 f2 4a 01 40 f9 ff 02 0a eb 48 00 ... 65486 more bytes, used: 0>,
_kMinPoolSpace: 128, from console.log(port)