Karl & all,

From:    karl@???
Date:    Mon,  8 Dec 2025 16:35:31 +0100 (CET)

> Is it so that you get a working console on serial port if you don't
> have the scsi card in the computer, but not if you add the scsi card ?

Correct.

> If so, try different pci slots for your scsi and serial cards,
> it can possible be some interrupt or other conflict.

This machine has 1 x (PCI), 2 x (PCIe_X1) and 1 x (PCIe_X16).

The SCSI card is PCI; only one location for it. The serial card is
PCIe_X1; two possible locations. The video card is PCIe_X16; only one
location.

Therefore a total of two configurations possible for the three cards.
Both give a constant black screen.

Hypothetically a logic analyzer can be applied. More practically, try
another SCSI card or serial card. Will see what is available.

> ... it might be so that
> serial --unit=0
> only is for a serial port at io-port 0x03f8 aka the classic DOS COM1
> and the kernel uses ttyS0 for a port at another io-port or some
> other confusion.

In GRUB, try --unit=1, 2, 3.

Yet after the kernel has become active, the console parameter should
produce output.

Other ideas?

Thanks,            ... P.

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