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Date: Mon, 25 May 2015 16:40:14 +0200
From: Pali =?utf-8?B?Um9ow6Fy?= <pali.rohar@gmail.com>
To: Darren Hart <dvhart@infradead.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Valdis Kletnieks <Valdis.Kletnieks@vt.edu>,
        lkml <linux-kernel@vger.kernel.org>,
        platform-driver-x86@vger.kernel.org,
        Matthew Garrett <mjg59@srcf.ucam.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: dell_rbtn - kernel panic at boot...
Message-ID: <20150525144014.GC23037@pali>
References: <5875.1432260403@turing-police.cc.vt.edu>
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 <201505230305.36633@pali>
 <20150525044432.GA38428@fury.dvhart.com>
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On Sunday 24 May 2015 21:44:32 Darren Hart wrote:
> On Sat, May 23, 2015 at 03:05:36AM +0200, Pali Rohár wrote:
> > On Saturday 23 May 2015 00:53:16 Dmitry Torokhov wrote:
> > > On Thu, May 21, 2015 at 7:06 PM, Valdis Kletnieks
> > > 
> > > <Valdis.Kletnieks@vt.edu> wrote:
> > > > So after I made both config variables =y, the resulting kernel
> > > > built, but died a glorious death at boot.
> > > 
> > > I guess if both are built-in then, according to link order,
> > > dell-laptop starts first, before dell-rbtn, and dies in
> > > dell_rbtn_notifier_register() in call to
> > > driver_for_each_device(&rbtn_driver.drv, ...) because rbtn_driver has
> > > not been registered yet and thus half-initlalized.
> > > 
> > > Thanks.
> > 
> > pr_debug() messages could be useful... but no idea if we can get them.
> > 
> > Is there any way to fix that dependency race condition? Could 
> > driver_attach() function call help?
> 
> I believe you can avoid this by moving dell-rbtn earlier in the Makefile than
> dell-laptop - but this is fragile and a hack to resolve a dependency problem.
> 

And what about that late_initcall() instead module_init() in dell-laptop?
Will it fix this problem?

-- 
Pali Rohár
pali.rohar@gmail.com