Re: [PATCH] clk: Allow drivers to build if COMPILE_TEST is enabled

[Krzysztof Kozlowski <k.kozlowski@samsung.com>]

On 15.10.2015 16:11, Javier Martinez Canillas wrote:
> Hello Krzysztof,
>>>>
>>>
>>> No, I only build tested on arm32 and x86. The 0-day bot haven't reported a
>>> build error yet and I didn't see any platform dependent code in the drivers.
>>
>> I see you guys with Luis are adding a lot of COMPILE_TEST. But
> 
> Yes, the motivation for this was that I've been helping Mauro with a big
> rework in the media subsystem [0] and was annoying to audit that all the
> drivers were converted to the new APIs and no compile regressions were
> introduced in drivers that could not be built with COMPILE_TEST enabled.
> 
> Most media drivers are able to be build though so I thought it would be
> a good idea to extend the build coverage in all the other subsystems.
> 
>> building only on these two architectures *is not enough*. Run at least
>> armv8, PPC and the x86_64. MIPS would be nice as well (I use the
>> CodeSourcery's MIPS). All of these (ARM64, X86_64, PPC, MIPS) can be
>> easily installed on typical debian-like Linux distro. Really easily.
>>
> 
> Thanks, Stephen also pointed out to the toolchains in kernel.org [1].
>  
>> By adding this non-tested build coverage you can actually fail some
>> other architecture's allyesconfig/allmodconfig builds.
>>
> 
> Agreed, unfortunately having more build coverage is not as trivial as I
> originally thought. Not only because it can break the build in obscure
> archs that I don't have a toolchain to test but also exposes more build
> warnings (as reported by the 0-day bot) that I've the bandwidth to fix.
> 
> So personally I'll stop trying to enabled COMPILE_TEST just to be safe.

I mean that in general I agree with the idea of COMPILE_TEST. I had
similar problems when I was changing the power supply API. Build testing
of each modified file required a lot of effort... but it was doable. I
just set up a configuration for build server doing all necessary archs
and configs. With COMPILE_TEST it would be much, much easier!

You don't have to give up entirely. Just use more compilers and in the
same time fix the warnings and errors. Send a patch fixing driver and
another one adding COMPILE_TEST.

Best regards,
Krzysztof