linux-kernel - Re: [PATCH v2] drivers/idle: make intel_idle.c driver more explicitly non-modular

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Message-ID: <20160421132137.GA18670@linaro.org>
Date:	Thu, 21 Apr 2016 15:21:37 +0200
From:	Daniel Lezcano <daniel.lezcano@...aro.org>
To:	Paul Gortmaker <paul.gortmaker@...driver.com>
Cc:	linux-kernel@...r.kernel.org, Len Brown <len.brown@...el.com>,
	rcochran@...utronix.de, linux-pm@...r.kernel.org
Subject: Re: [PATCH v2] drivers/idle: make intel_idle.c driver more
 explicitly non-modular

On Thu, Apr 21, 2016 at 08:44:55AM -0400, Paul Gortmaker wrote:
> [Re: [PATCH v2] drivers/idle: make intel_idle.c driver more explicitly non-modular] On 21/04/2016 (Thu 10:04) Daniel Lezcano wrote:
> 
> > On Wed, Apr 20, 2016 at 11:12:49PM -0400, Paul Gortmaker wrote:
> > 
> > [ ... ]
> > 
> > > > > We replace module.h with moduleparam.h since the file does declare
> > > > > some module parameters, and leaving them as such is currently the
> > > > > easiest way to remain compatible with existing boot arg use cases.
> > > > 
> > > > What about using __setup() ? so module* disappear from the file.
> > > 
> > > No, it can't be __setup since moduleparam uses an instance of the
> > > filename as a prefix to the boot arg, and __setup does not.  And we
> > > should stay compatible with existing boot arg use cases for people
> > > who have embedded such a setting in their grub config a long time
> > > ago and forgot it.  It would take looking at and likely extending the
> > > early_param macro to provide a syntax compatible instance of what
> > > the module_param currently does if I recall correctly -- hence the
> > > above comment in the commit log.
> > 
> > -module_param(max_cstate, int, 0444);
> > +static int __init max_cstate_param(char *str)
> > +{
> > +       max_cstate = simple_strtol(str, NULL, 0);
> > +       return 1;
> > +}
> > +__setup("intel_idle.max_cstate=", max_cstate_param);
> 
> Yeah, I recall thinking it would be that easy too, but there was
> something that happens when you manually insert the dot in there that
> breaks processing.  I'd have to re-test to remind myself what failed.

Ok.

I quickly tested this code snippet and, except I missed something, it 
worked.

That said, I looked around and found that using module_param() for 
non-modular is found in several places, so it is common. I don't like to 
find references to modular code when the the caller is not supposed to be 
modular but that's the situation today.

So I will let Len and you decice what to do ;)

Other than that: Acked-by: Daniel Lezcano <daniel.lezcano@...aro.org>