On 07/17/2014 06:38 PM, Arnd Bergmann wrote:

On Thursday 17 July 2014 17:29:31 Chen Gang wrote:

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COMPILE_TEST is a great tool in general, but it has its limits.
In particular, the case for !CONFIG_IOMEM is completely obscure
and we won't find any bugs by allowing more drivers to be built
in those configurations, but attempting to do it would cause
endless churn by changing each instance of 'depends on HAS_IOMEM'
to 'depends on HAS_IOMEM || COMPILE_TEST'.

Architecture members and driver members really have different tastes,
they are different roles. It really need additional discussion.

For me, I only want to change devm_io*map*, not touch so much.

But what do you gain from that? All drivers that need these
functions should already 'depends on HAS_IOMEM' and if they don't,
we should fix /that/ instead. I don't see this dependency as any
different from a lot of others (PCI, DMAENGINE, HAVE_CLK, ...)
that we use to intentionally annotate drivers that need a particular
feature to be present for compilation. Do you want to do the
same hack to those?

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Welcome any other members' idea or suggestions.

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Note that s390 no has gained support for IOMEM, tile has it most
of the time (when PCI is enabled, so you get it in half the
test builds already), score should set HAS_IOMEM and doesn't
even have public compilers, and uml doesn't even compile in
latest mainline. Nothing else ever sets NO_IOMEM.

I guess, we are just discussing about them in another threads, so I skip
them. If it is still necessary to reply (e.g. I misunderstand), please
let me know, thanks.

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In latest gcc and binutils, can compile score cross compiler
successfully for building kernel (but I am not quite sure whether the
compiling result are really OK, but I guess so).

Ok. Would you mind sending a patch that enables HAS_IOMEM on
score?
 

For me, welcome the score related maintainers' idea and suggestions.

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And next (maybe after finish allmodconfig for microblaze), I shall try
to let uml pass allmodconfig for linux-next tree.

That is a fair goal, but it seems better to do that by ensuring
we don't build any code that tries to call the MMIO functions
rather than trying to make them build.

When I am performing uml, I will try and also communicate with the
related maintainers for it (their suggestions and ideas are valuable).

Thanks.
-- 
Chen Gang

Open, share, and attitude like air, water, and life which God blessed