Re: [PATCH] [v3] serial: 8250: remove obsolete and broken PORT_RSA support

[Arnd Bergmann]

On Thu, Oct 22, 2026, at 05:34, Maciej W. Rozycki wrote:
> On Wed, 21 Oct 2026, Arnd Bergmann wrote:
>
>> >  Or, to self-correct after a few more mind cycles spent on this piece, the 
>> > region below `port->iobase' is an expansion of one above, where standard 
>> > 8250 registers of the onboard serial port reside.  Which makes even more 
>> > sense, to me anyway.
>> 
>> Good catch, so it should still work the same way it was originally
>> designed, though I think it still requires a modified setserial to
>> set PORT_RSA, or a boot time argument for autoconfiguration with
>> UART_CONFIG_TYPE.
>
>  Well, this is ISA, what do you expect?  We've dropped lots of stuff that 
> required perhaps even more complex manual configuration already (QIC-02 
> tapes, anyone?).

I pointed it out because this is the only UART driver that relies on
that specific mechanism. Everything else uses either hardcoded port
numbers that like the 3f8/2f8/3e8/2e8 ports for PC compatibility or
they rely on PnP. I understand that we have other network/scsi/sound/iio
drivers that also do this.

    Arnd