Re: Smarter Kconfig help - Russell King

From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Lucas Stach <l.stach@pengutronix.de>
Cc: linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, Mark Rutland <mark.rutland@arm.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Andy Shevchenko <andy.shevchenko@gmail.com>,
	Peng Hao <peng.hao2@zte.com.cn>
Subject: Re: Smarter Kconfig help
Date: Wed, 6 Mar 2019 09:51:47 +0000	[thread overview]
Message-ID: <20190306095147.xyf3d62bywx4v6ji@shell.armlinux.org.uk> (raw)
In-Reply-To: <1551865552.9298.24.camel@pengutronix.de>

On Wed, Mar 06, 2019 at 10:45:52AM +0100, Lucas Stach wrote:
> Hi Russell,
> 
> Am Dienstag, den 05.03.2019, 17:31 +0000 schrieb Russell King - ARM Linux admin:
> > Guys,
> > 
> > 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.
> > 
> > IMX_IRQSTEER - which i.MX SoCs does this apply to?  The help text
> > just says:
> > 
> >   "Support for the i.MX IRQSTEER interrupt multiplexer/remapper."
> > 
> > which doesn't say which SoCs this should be enabled for - it turns
> > out that grepping for the driver's DT compatible string, none of
> > the 32-bit ARM cores have support for this, yet we still default
> > it to enabled there.  It seems the help text should at the very
> > least tell the user that this is not applicable to i.MX SoCs with
> > 32-bit ARM cores.
> > 
> > I'm sure there's many other instances of this... I suspect that
> > it's caused by review concentrating mostly on the technical aspects
> > of the code and the Kconfig help text just gets forgotten about.
> > 
> > Can we at least improve these two options please?
> 
> While I totally agree that the irqsteer driver should only default Y on
> 64bit i.MX SoCs, I'm not really sure what to do about the Kconfig help
> text.
> 
> Enumerating SoCs in the Kconfig of a IP block driver is always prone to
> get outdated. Just as the first example I've been able to come up with,
> the MMC_SDHCI_ESDHC_IMX help text says: "This selects the Freescale
> eSDHC/uSDHC controller support found on i.MX25, i.MX35 i.MX5x and
> i.MX6x.", while the same IP block is to be found on i.MX7 and various
> i.MX8.
> 
> For the Kconfig user, who needs to decide if an option is relevant,
> outdated SoC information is probably just as bad as no information at
> all.

How about "This option does not apply to AArch32 based SoCs" or
"This option should be enabled for i.MX7 and later SoCs" ?

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