Re: [PATCH V3 2/8] drivers: boot_constraint: Add boot_constraints_disable kernel parameter

From: Greg Kroah-Hartman
Date: Tue Aug 29 2017 - 07:56:12 EST


On Tue, Aug 29, 2017 at 12:02:41PM +0200, Viresh Kumar wrote:
> On 29-08-17, 08:37, Greg Kroah-Hartman wrote:
> > On Tue, Aug 01, 2017 at 02:53:43PM +0530, Viresh Kumar wrote:
> > > + boot_constraints_disable
> > > + Do not set any boot constraints for devices.
> >
> > Shouldn't that be the default? As really, that is what the situation is
> > today, why force everyone to always enable the disable value? And
> > enabling a value to disable something is usually a sign of bad naming...
>
> I will explain once again how it is getting used and then will do whatever you
> suggest.
>
> - Platforms that don't need boot constraints should not enable the CONFIG in the
> first place. Though we use the same kernel image on multiple hardware types
> many times.

Right, which means this is useless as an option, don't ever rely on it
:)

> - If a platform doesn't have a platform-specific driver that adds constraints at
> boot, then the boot constraint core wouldn't get into picture at all and it is
> as good as being disabled.

Possibly, but see above for the goal of one kernel image, many different
devices.

> - And the above boot-argument (boot_constraints_disable) is used ONLY in the
> case where the platform driver is adding boot constraints at runtime.
>
> So, the boot-constraints are disabled by default for everyone even if the
> configuration is enabled. And that's why I named it the way it is right now.
>
> Do you still feel that it needs to be renamed?

Well, negative options are ackward (although usb_disable is an
option...) It still feels wrong, and I worry about the above
single-image goal...