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

[Maciej W. Rozycki]

On Mon, 19 Oct 2026, Arnd Bergmann wrote:

> The driver defines an I/O port base address of -8 (negative eight),
> which should always get refused by request_region on all architectures
> for being outside of the valid resource range.

 For completeness only since I have nothing to do with this hardware: it 
does not appear to me that the negative offset ought to cause any refusal.  
In rsa8250_request_resource() we currently have:

	start = UART_RSA_BASE << port->regshift;
	start += port->iobase;
	size = 8 << port->regshift;

	if (!request_region(start, size, "serial-rsa"))
		return -EBUSY;

so the only peculiarity is that the 8-byte region requested is actually 
below `port->iobase', presumably relative to standard ISA serial port port 
I/O locations of 0x3f8, 0x2f8, 0x3e8, 0x2e8, possibly not to clash with 
conventional ISA serial port devices where also present in a system (for 
simplicity assuming that `port->regshift' is 0; adjust the calculations 
accordingly if not).  So offhand nothing wrong here and please consider 
discarding the paragraph.

  Maciej