My singleboard compter (SBC) have 4-UART ports. They all use one IRQ with different addresses. SBC BIOS can not divide them all on different IRQ (only 2 IRQ for them). Then i setup only one port using configure command all ports work normally. But when i setup 2 of them in one boot configuration i get in dmesg:
irq already in use
How to avoid that error? On Linux & QNX all works OK.