Re: [PATCH] Remove remaining references of CONFIG_GENERIC_TIME

From: Kyle Moffett
Date: Mon Aug 01 2011 - 11:15:51 EST


On Mon, Aug 1, 2011 at 11:04, Arnaud Lacombe <lacombar@xxxxxxxxx> wrote:
> Hi,
>
> On Mon, Aug 1, 2011 at 7:27 AM, Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
>> On Mon, Aug 1, 2011 at 12:14, Russell King - ARM Linux
>> <linux@xxxxxxxxxxxxxxxx> wrote:
>>> On Mon, Aug 01, 2011 at 12:09:02PM +0200, Geert Uytterhoeven wrote:
>>>> On Mon, Aug 1, 2011 at 10:36, Russell King - ARM Linux
>>>> <linux@xxxxxxxxxxxxxxxx> wrote:
>>>> > On Sat, Jul 30, 2011 at 06:14:38PM +0200, Zoltan Devai wrote:
>>>> >> Commit 592913ecb87a9e06f98ddb55b298f1a66bf94c6b has killed off any
>>>> >> use of this config option long ago.
>>>> >
>>>> > I don't see the point of this - we were free of GENERIC_TIME on ARM
>>>> > shortly after it was originally killed off. ÂThe problem is you can't
>>>> > stop people introducing new uses of this - because it existed once and
>>>> > there's nothing which errors out on its presence, people are going to
>>>> > continue submitting patches with it in. ÂAnd it's going to continue
>>>> > being missed at the review stage.
>>>> >
>>>> > I've a similar problem with folk on ARM including mach/gpio.h as their
>>>> > sole gpio header file rather than linux/gpio.h - I've been trying for
>>>> > the last 1-2 years to educate people to use linux/ in preference. ÂYou
>>>> > can't do it, and I'm still just about the only one who picks up on that.
>>>> > (SoC maintainers don't care.) ÂThey will end up caring when I push a
>>>> > change during the next merge window though, so I'll eventually stop
>>>> > mach/gpio.h being included. Â(Instead, it'll be asm/gpio.h).
>>>> >
>>>> > GENERIC_TIME though... I don't think you'll ever stop new uses of it
>>>> > creeping in unless you can arrange for something to error out.
>>>>
>>>> Doesn't kconf error out when trying to select a non-existent symbol?
>>>
>>> Nope.
>>
>> You're right. So that's a bug.
>>
> depends on what you are trying to achieve and what the problem is.
>
> Internally kconfig will create a dummy symbol when it encounter a
> missing symbol so that arch/arm/Kconfig can reference a symbol which
> will be fully defined later on. I do not think you want to forward
> decl all the symbol which can be used. That'd be a mess. That said, we
> can come with a form of symbol deprecation that would error-out when
> used.

Would it be possible instead to make Kconfig go through all the symbols
after everything is processed and identify any remaining "dummy symbols"
which were not actually declared anywhere?

Right now if you typo a "select" statement you get no warnings that you
are selecting something that does not exist, which is probably a cause
of many kinds of errors beyond this particular one.

Cheers,
Kyle Moffett
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