Greetings Devuan!

I am trying to use onboard RS-232 @ supermicro A1Sai-2750 with Intel
C2750, Devuan Chimaera, vanilla kernel 5.10.0-10-amd64. In BIOS the
ports COM1 and COM2 are configured on 24MHz/13.

In dmesg I can see:
"/Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled/"
but no tty (except console), and receive IO errors on /cat /dev/ttySx/,
and on /stty -F /dev/ttySx/


Searching brought me to the kernel rebuild with options like
CONFIG_SERIAL_8250_PCI, which are already enabled in current kernel.
Tried to load 8250_lpss.ko too, with no luck.

Shortcut would be to use the USB RS-232 dongle, however it will be too
easy, I guess, and boring too.

Can you give me some light, please? Many thanks!
Andrzej