Non-standard baud rate support issue in jSerialComm versions newer than 2.9.3 on Raspberry Pi OS Lite 64-bit #579

Issue Summary:
I'm experiencing an issue with jSerialComm library versions newer than 2.9.3 on Raspberry Pi OS Lite 64-bit when attempting to open a serial port (/dev/ttyS0) at a non-standard baud rate of 420000. Version 2.9.3 opens the port as expected, but all later versions fail, returning error code 25 (Resource Busy). However, standard baud rates (9600, 115200, and 921600) work perfectly across all versions.

Details:

• Platform: Raspberry Pi Zero 2 W with Raspberry Pi OS Lite 64-bit
• Library Version Comparison:
  • Version 2.9.3: Successfully opens /dev/ttyS0 at 420000 baud rate. No error is reported.
  • Versions > 2.9.3 (e.g., 2.11.0): Fail to open /dev/ttyS0 at 420000 baud rate, returning error code 25 (Resource Busy).
  • Standard Baud Rates (9600, 115200, 921600): Work consistently across all versions.

Logs:

• Using jSerialComm Version 2.9.3 (420000 baud):

  Using SerialPort Library Version v2.9.3
  Opening ttyS0: Physical Port S0, Baud rate 420000: OK
  Last error code: 0
  

• Using jSerialComm Versions > 2.9.3 (e.g., 2.11.0) with 420000 baud:

  Using SerialPort Library Version v2.11.0
  Opening ttyS0: Physical Port S0, Baud rate 420000: FAIL
  Last error code: 25
  

Steps to Reproduce:

1. Set up jSerialComm on Raspberry Pi OS Lite 64-bit.
2. Attempt to open a serial port (e.g., /dev/ttyS0) at a baud rate of 420000 in versions newer than 2.9.3.
3. Note that version 2.9.3 successfully opens the port, while all newer versions fail. Standard baud rates (9600, 115200, and 921600) work without issue across all versions.

Expected Behavior:
Non-standard baud rates, such as 420000, should be consistently supported across all jSerialComm versions on compatible hardware and operating systems.