Re: ARM defconfig files

[Russell King <rmk@arm.linux.org.uk>]

On Thu, Jun 03, 2010 at 12:49:58PM -0700, Daniel Walker wrote:
> On Thu, 2010-06-03 at 20:45 +0100, Russell King wrote:
> > On Thu, Jun 03, 2010 at 12:35:42PM -0700, Daniel Walker wrote:
> > > On Thu, 2010-06-03 at 11:56 -0700, Linus Torvalds wrote:
> > > > 
> > > > On Thu, 3 Jun 2010, Russell King wrote:
> > > > > 
> > > > > No amount of reorganising the Kconfig files into a heirarchial manner
> > > > > (which they already are) helps.  Not one bit.  Because they already are.
> > > > > That's not where the problem is.
> > > > 
> > > > I don't think you read the whole thread.
> > > > 
> > > > Earlier on, I explained exactly what I wanted: just add some "select" 
> > > > statements to pickt he things you need per the particular target 
> > > > configuration. You seem to have missed that part.
> > > > 
> > > > In other words, you _can_ encode the information that is in the 
> > > > xyz_defconfig files by doing it in Kconfig.xyz files instead. But you do 
> > > > it in a human-readable manner. And the hierarchical thing is absolutely 
> > > > required for that - otherwise you'd end up with just another form of the 
> > > > current xyz_defconfig.
> > > > 
> > > > See?
> > > > 
> > > > In other words, you should be able to basically use "make allnoconfig" 
> > > > together with a Kconfig.xyz file input to select _exactly_ the pieces you 
> > > > need, and nothing else.
> > > 
> > > If you did this for drivers, what about disabling a driver? If we used
> > > "select" wouldn't that force all the drivers on without allowing it to
> > > be unselected?
> > 
> > I already covered that in my (ignored) email where I brought up a
> > "STD_CONFIG" config symbol, which could be disabled to turn off all
> > these additional "select"s.
> 
> I didn't ignore it, I guess I just didn't fully understand it ..
> 
> So your saying it would drop all the selects, but keep the selected
> options in tact? Or it would just turn off all the selected options?

config MACH_HALIBUT
	bool "Halibut Board (QCT SURF7201A)"
	select I2C if STD_CONFIG
	select I2C_WHATEVER if STD_CONFIG
	...

That means if you enable STD_CONFIG, you'll get everything that's required
selected.  If you then disable STD_CONFIG, I believe Kconfig leaves
everything that was selected as still being selected.

So, what you _could_ do is start off with a blank configuration, then
configure a kernel with STD_CONFIG enabled and you end up with everything
that's required.  If you then want to disable something that's selected,
turn off STD_CONFIG first, and you'll be able to turn off individual
options.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of: