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From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>
Date: Mon, 8 Apr 2024 13:25:15 +0300 (EEST)
To: Arnd Bergmann <arnd@kernel.org>
cc: Niklas Schnelle <schnelle@linux.ibm.com>, 
    Greg Kroah-Hartman <gregkh@linuxfoundation.org>, 
    Jiri Slaby <jirislaby@kernel.org>, 
    linux-serial <linux-serial@vger.kernel.org>, 
    Heiko Carstens <hca@linux.ibm.com>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/1] tty: serial: handle HAS_IOPORT dependencies
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Message-ID: <e4299a49-eeef-da89-2806-377d62b417e2@linux.intel.com>
References: <20240405152924.252598-1-schnelle@linux.ibm.com> <20240405152924.252598-2-schnelle@linux.ibm.com> <1a14ac6e-30e9-048e-50cc-c1c3aacc2118@linux.intel.com> <80c20c7b-4e7a-43af-8b59-7f2a98272e99@app.fastmail.com>
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On Mon, 8 Apr 2024, Arnd Bergmann wrote:

> On Mon, Apr 8, 2024, at 11:54, Ilpo J=C3=A4rvinen wrote:
> > On Fri, 5 Apr 2024, Niklas Schnelle wrote:
>=20
> >>  config SERIAL_8250_CS
> >>  =09tristate "8250/16550 PCMCIA device support"
> >> -=09depends on PCMCIA && SERIAL_8250
> >> +=09depends on PCMCIA && SERIAL_8250 && HAS_IOPORT
> >>  =09help
> >>  =09  Say Y here to enable support for 16-bit PCMCIA serial devices,
> >>  =09  including serial port cards, modems, and the modem functions of
> >
> > What about drivers that use SERIAL8250_PORT()?
>=20
> 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.
>=20
> > Also port provided in 8250_PNP might expect it I think.
>=20
> 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.
>=20
> 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.

--=20
 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.

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