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Date: Tue, 24 Mar 2015 07:39:16 +0000
From: "Jan Beulich" <JBeulich@suse.com>
To: "Paul Bolle" <pebolle@tiscali.nl>, "Martin Walch" <walch.martin@web.de>
Cc: <akpm@linux-foundation.org>, "Sam Ravnborg" <sam@ravnborg.org>,
        "Michal Marek" <mmarek@suse.cz>, <linux-kbuild@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Kconfig: drop bogus default values
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>>> On 23.03.15 at 23:58, <walch.martin@web.de> wrote:
> On Monday 23 March 2015 22:24:28 Paul Bolle wrote:
>> > A real world case is PCI_QUIRKS in the mainline kernel:
>> > 
>> > init/Kconfig:1554:	default y
>> > arch/s390/Kconfig:59:	def_bool n
>> > 
>> > When setting PCI!=n && EXPERT=n then on each architecture PCI_QUIRKS=y
>> > except on s390 where PCI_QUIRKS=n.
>> 
>> Good catch!
>> 
>> For the same effect, would it do to have
>>     config PCI_QUIRKS
>>         default y if !S390
>>         [...]
>> 
>> in init/Kconfig?
> 
> Basically yes (although I suppose the maintainer had a good reason for
> writing it the way it is now). But in the case with "def_bool n" in
> arch/s390/Kconfig, the default value is explicitly set to n, while
> "default y if !S390" does not set the value at all. As long as there are no
> further default lines for PCI_QUIRKS below, this leads to the same
> configuration. However if there was a third default line, then in the former
> case that third default value would be always ignored while in the latter
> case it would determine the default value on s390.

If the "n" default was really needed, it could be

config PCI_QUIRKS
         default !S390

Jan