On 07/01/2013 03:32 PM, Geert Uytterhoeven wrote:

On Mon, Jul 1, 2013 at 8:44 AM, Chen Gang [off-list ref] wrote:

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On 07/01/2013 02:34 PM, Richard Weinberger wrote:

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config COMPILE_TEST

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        bool "Compile also drivers which will not load"
        default n
        help
          Some drivers can be compiled on a different platform than they are
          intended to be run on. Despite they cannot be loaded there (or even
          when they load they cannot be used due to missing HW support),
          developers still, opposing to distributors, might want to build such
          drivers to compile-test them.

          If you are a developer and want to build everything available, say Y
          here. If you are a user/distributor, say N here to exclude useless
          drivers to be distributed.

I guess, 'COMPILE_TEST' is really useful for UML.

No.

We have explained you more than once what the deal and why UML does not
have ioremap() and friends.

This time, it is not for UML, it is for 'COMPILE_TEST': the
'asm-generic' whether need consider it.

COMPILE_TEST is only meant to be used as a dependency in Kconfig files,
to make drivers that cannot work due to missing hardware invisible when
configuring your kernel.

Why "Despite they cannot be loaded there (or even when they load they
cannot be used due to missing HW support)" ?

There should be no #ifdefs in actual code that check for (the lack of)
CONFIG_COMPILE_TEST.

In ideal world, it should be no #ifdefs for all "CONFIG_*" in 'normal code'.

But "asm-generic" are not belong to 'normal code', it is one of the main
place to process "CONFIG_*".

If the platforms need support 'COMPILE_TEST', the asm-generic is the
main place for implementing it.


So I think our focus is on "whether the platforms guys need support
'COMPILE_TEST" for modules guys".


Thanks
-- 
Chen Gang