Re: [PATCH 1/2] [v4] serial: 8250: remove obsolete PORT_RSA support

[Andy Shevchenko]

On Wed, Oct 21, 2026 at 10:17:45AM +0200, Arnd Bergmann wrote:

> For all I can tell, the RSA support in the 8250 driver is not functional
> and has not been for a long time.
> 
> The RSA-DV II/S ISA card[1] was sold by IODATA in the 1990s as a faster
> alternative to regular ISA serial ports, and it was discontinued in
> 2002. Linux support was added by Kiyokazu SUTO in 2000[2]. The company
> also made PCI versions of this device, but Linux never supported those.
> 
> It seems that a patch to setserial would be required in order to set
> PORT_RSA when not using autoconfiguration, and this was never merged.
> Autotoconfiguration in turn requires passing probe_rsa=IOPORT arguments
> at boot or module load time, which is not how any other uart drivers
> work any more since linux-2.4.
> 
> This patch removes all code related to the RSA support, with the exception
> of the user-visible PORT_RSA definition. I had originall sent this in
> 2011 [3], but did not follow up at the time.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>

-- 
With Best Regards,
Andy Shevchenko