Re: [PATCH 1/1] tty: serial: handle HAS_IOPORT dependencies

[Ilpo Järvinen]

On Mon, 8 Apr 2024, Arnd Bergmann wrote:

> On Mon, Apr 8, 2024, at 11:54, Ilpo Järvinen wrote:
> > On Fri, 5 Apr 2024, Niklas Schnelle wrote:
> 
> >>  config SERIAL_8250_CS
> >>  	tristate "8250/16550 PCMCIA device support"
> >> -	depends on PCMCIA && SERIAL_8250
> >> +	depends on PCMCIA && SERIAL_8250 && HAS_IOPORT
> >>  	help
> >>  	  Say Y here to enable support for 16-bit PCMCIA serial devices,
> >>  	  including serial port cards, modems, and the modem functions of
> >
> > What about drivers that use SERIAL8250_PORT()?
> 
> It probably makes sense to hide these, since they won't ever
> work. I probably missed them in my initial series because they
> don't cause a compile-time error, but I agree that there is no
> use in showing the options here.
> 
> > Also port provided in 8250_PNP might expect it I think.
> 
> I don't think these need any change: 8250_pnp.c supports
> both IORESOURCE_IO and IORESOURCE_MEM based ports. It will
> still create a 8250 port for the I/O based ones but they
> will now correctly fail to probe in the main driver rather
> than crashing the kernel. PNP devices that only use
> memory BARs will keep working as before, on both machines
> with and without CONFIG_HAS_IOPORT.
> 
> I think that most 8250_pnp variants are probably used only
> with ISAPNP or PNPBIOS, neither of which exists without
> HAS_IOPORT,

Okay, seems fine then if that dependency is handled somewhere.

-- 
 i.

> but you could certainly have PNPACPI on arm
> or riscv machines that don't have port I/O but come with
> a memory-mapped 8250 port described by firmware.