Re: Smarter Kconfig help - Russell King

From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Mark Rutland <mark.rutland@arm.com>
Cc: Peng Hao <peng.hao2@zte.com.cn>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-kernel@vger.kernel.org,
	Andy Shevchenko <andy.shevchenko@gmail.com>,
	linux-arm-kernel@lists.infradead.org,
	Lucas Stach <l.stach@pengutronix.de>
Subject: Re: Smarter Kconfig help
Date: Wed, 6 Mar 2019 12:50:22 +0000	[thread overview]
Message-ID: <20190306125022.ikqy66lf25yifxwc@shell.armlinux.org.uk> (raw)
In-Reply-To: <20190306093521.GA50994@lakrids.cambridge.arm.com>

Hi Mark,

On Wed, Mar 06, 2019 at 09:35:21AM +0000, Mark Rutland wrote:
> On Tue, Mar 05, 2019 at 05:31:12PM +0000, Russell King - ARM Linux admin wrote:
> > Guys,
> 
> Hi Russell,
> 
> > We need to be smarter when writing Kconfig help.  I'm just going
> > through updating my build trees with the results of 5.0 development,
> > and a number of the help texts are next to useless.  For example,
> > 
> > PVPANIC - is this something that should be enabled for a host or
> > guest kernel?  Answer: you have to read the driver code to find out.
> 
> When I looked at the help text:
> 
>     This driver provides support for the pvpanic device.  pvpanic is
>     a paravirtualized device provided by QEMU; it lets a virtual machine
>     (guest) communicate panic events to the host.
> 
> ... it seemed clear to me that this was for a guest, given the text says
> QEMU provides the device. I guess you read that as meaning QEMU asks the
> host kernel to provide the device to the guest?

Yes - that's exactly where the confusion was.  It could be something
like a tap network device to allow a guest access to a facility on the
host, or it could be something that the guest kernel uses to communicate
with its host environment.

> Do you have a suggestion for how to word that unambiguously?

It used to be normal to include a sugestion in the help text that
guided when an option should be enabled.  So, adding something like:

    "Say Y here if you are building a kernel for a virtual machine."

would make it clear.  This used to be standard throughout the kernel,
but it seems in recent years, this has been omitted.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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