Read always timeout in arm-unknown-linux-musleabihf about serialport-rs

[sirhcel]

Hello @pandakka, this looks strange indeed. If there is data on the rx line after the port gets opened, than I would expect it to be received.

Just the overcautious question: Is there actually data sent to the serial port you are running the snipped above on?

Could you please cross-check the reception of data with this serial port using a second adapter, crossed RX and TX lines, and hardware_check.rs from the latest main branch? For example:

$ cargo run --release --example hardware_check -- --loopback-port /dev/tty.usbserial-11230 /dev/tty.usbserial-11240

Transmitting data back and forth between these two serial ports, should report success like (at least for the test cases not using flow control):

Testing paired ports '/dev/tty.usbserial-11240' and '/dev/tty.usbserial-11230':
  Transmitting from /dev/tty.usbserial-11240 to /dev/tty.usbserial-11230...
     At 2000000,8,n,1,noflow...
        success
        success
     At 115200,8,n,1,noflow...
        success
        success
     At 57600,8,n,1,noflow...
        success
        success
     At 10000,8,n,1,noflow...
        success
        success
     At 9600,8,n,1,noflow...
        success
        success
     At 9600,8,n,1,softflow...
        success
        success
     At 9600,8,n,1,hardflow...
        success
        success

[pandakka]

@sirhcel Thank for your help ! Thank you for your advice， that I find my embedded linux board have a little diffent from PC,which need take some special setting 😓
Now it works. Thanks again : )

[sirhcel]

I'm glad to hear that! So there is nothing more to do here.

May I just ask out of curiosity what finally caused the data not being received?

[pandakka]

Maybe is my first time touch embedded programing, I try a lot and find the path is /dev/ttymxc3 😂.
By the way available_ports() works well on my pc .But on my board side file style in "/sys/class/tty/ttymxc3/device/* is different ,which may cause the function() can't find the port ,so i need try by my hand😂.

[sirhcel]

This sounds like you are running into #66 on your embedded device. On Linux without libudev, the enumeration is done using sysfs and apparently the paths from /sys and not the actual devices files from /dev are returned.

What's your environment on the target? Is udev really not available there? How are you buildilng serialport-rs and your application for the embedded target? Could you please leave a comment in #66 if you are building without udev support?