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Date: Sat, 22 Mar 2025 08:11:23 +0100
From: Ingo Molnar <mingo@kernel.org>
To: david@ixit.cz
Cc: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
	"H. Peter Anvin" <hpa@zytor.com>, Kees Cook <kees@kernel.org>,
	Jonathan Cameron <jic23@kernel.org>,
	Lars-Peter Clausen <lars@metafoo.de>, linux-kernel@vger.kernel.org,
	linux-iio@vger.kernel.org,
	Mateusz =?utf-8?Q?Jo=C5=84czyk?= <mat.jonczyk@o2.pl>
Subject: Re: [PATCH v3 5/7] x86/Kconfig: Document CONFIG_PCI_MMCONFIG
Message-ID: <Z95im-uBoWJHmoX7@gmail.com>
References: <20250321-x86_x2apic-v3-0-b0cbaa6fa338@ixit.cz>
 <20250321-x86_x2apic-v3-5-b0cbaa6fa338@ixit.cz>
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* David Heidelberg via B4 Relay <devnull+david.ixit.cz@kernel.org> wrote:

> From: Mateusz Jończyk <mat.jonczyk@o2.pl>
> 
> This configuration option had no help text, so add it.
> 
> CONFIG_EXPERT is enabled on some distribution kernels, so people using a
> distribution kernel's configuration as a starting point will see this
> option.
> 
> Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
> Signed-off-by: David Heideberg <david@ixit.cz>
> ---
>  arch/x86/Kconfig | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index fbc9ba30fd1cbfb574399a0632b9f77876ba84a8..64a1e00619df95f559488e3004558a7b0f653df3 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -2914,6 +2914,19 @@ config PCI_MMCONFIG
>  	default y
>  	depends on PCI && (ACPI || JAILHOUSE_GUEST)
>  	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
> +	help
> +	  Add support for accessing the PCI configuration space as a memory
> +	  mapped area. It is the recommended method if the system supports
> +	  this (it must have PCI Express and ACPI for it to be available).
> +
> +	  In the unlikely case that enabling this configuration option causes
> +	  problems, the mechanism can be switched off with the 'pci=nommconf'
> +	  command line parameter.
> +
> +	  Say 'n' only if you are sure that your platform does not support this
> +	  access method or you have problems caused by it.
> +
> +	  Say 'y' otherwise.

For future reference, the canonical incantantion in Kconfig lore is:

	  Say Y otherwise.

I have fixed it up in this commit.

Thanks,

	Ingo