Re: [Intel-gfx] [PATCH 1/7] drm/i915/hwmon: Add HWMON infrastructure

[Jani Nikula <jani.nikula@linux.intel.com>]

On Tue, 23 Aug 2022, Guenter Roeck <linux@roeck-us.net> wrote:
> On Tue, Aug 23, 2022 at 12:46:14PM +0300, Jani Nikula wrote:
> [ ... ]
>> >> 
>> >> So why not do this in i915 Kconfig:
>> >> 
>> >> config DRM_I915
>> >> 	...
>> >> 	depends on HWMON || HWMON=n
>> > With this change I am getting recursive dependancy error when I run make 
>> > oldconfig
>> >
>> > badal@bnilawar-desk1:~/workspace/wp3/drm-tip$ make oldconfig
>> >    HOSTCC  scripts/basic/fixdep
>> >    HOSTCC  scripts/kconfig/conf.o
>> >    HOSTCC  scripts/kconfig/confdata.o
>> >    HOSTCC  scripts/kconfig/expr.o
>> >    LEX     scripts/kconfig/lexer.lex.c
>> >    YACC    scripts/kconfig/parser.tab.[ch]
>> >    HOSTCC  scripts/kconfig/lexer.lex.o
>> >    HOSTCC  scripts/kconfig/menu.o
>> >    HOSTCC  scripts/kconfig/parser.tab.o
>> >    HOSTCC  scripts/kconfig/preprocess.o
>> >    HOSTCC  scripts/kconfig/symbol.o
>> >    HOSTCC  scripts/kconfig/util.o
>> >    HOSTLD  scripts/kconfig/conf
>> > drivers/gpu/drm/i915/Kconfig:2:error: recursive dependency detected!
>> > drivers/gpu/drm/i915/Kconfig:2: symbol DRM_I915 depends on HWMON
>> > drivers/hwmon/Kconfig:6:        symbol HWMON is selected by EEEPC_LAPTOP
>> > drivers/platform/x86/Kconfig:332:       symbol EEEPC_LAPTOP depends on INPUT
>> > drivers/input/Kconfig:8:        symbol INPUT is selected by DRM_I915
>> > For a resolution refer to Documentation/kbuild/kconfig-language.rst
>> > subsection "Kconfig recursive dependency limitations"
>> 
>> *sigh*
>> 
>>   Note:
>> 	select should be used with care. select will force
>> 	a symbol to a value without visiting the dependencies.
>> 	By abusing select you are able to select a symbol FOO even
>> 	if FOO depends on BAR that is not set.
>> 	In general use select only for non-visible symbols
>> 	(no prompts anywhere) and for symbols with no dependencies.
>> 	That will limit the usefulness but on the other hand avoid
>> 	the illegal configurations all over.
>> 
> Agreed. HWMON should not be selected anywhere. Unfortunately it is, and
> drm is no exception. It is selected by DRM_RADEON and DRM_AMDGPU.
> Maybe just select it in DRM_I915 as well after all; in practice it won't
> make a difference.

And I guess everyone just does what I'm about to do now, throw my hands
up in the air in disgust and resignation. :p

BR,
Jani.



-- 
Jani Nikula, Intel Open Source Graphics Center