[PATCH 3/8] drm/display: Introduce a DRM display-helper module

[Thomas Zimmermann]

Hi Jani

Am 07.04.22 um 10:45 schrieb Jani Nikula:
...
>>
>> I think another idea that could work is to use an intermediate symbol.
>> For DP, drivers would select the tristate DP_HELPER, which in turn
>> selects tristate DISPLAY_HELPER and boolean DISPLAY_DP_HELPER.  But this
>> would require a 'useless' symbol DP_HELPER only for convenience.  It's
>> an even less optimal solution, it seems.
> 
> Documentation/kbuild/kconfig-language.rst:
> 
>    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.
> 
> Most of the difficult Kconfig issues I've encountered over the years
> come from not following the above two rules. People break those rules
> for "convenience", causing a lot of inconvenience down the line.

I have meanwhile updated the patchset and all new boolean options are 
internal. No select will be performed on 'visible' symbols. So it should 
be fine.

Best regards
Thomas

> 
> 
> BR,
> Jani.
> 
> 
>>
>> Best regards
>> Thomas
>>
>>>    --
>>> Best regards,
>>>
>>> Javier Martinez Canillas
>>> Linux Engineering
>>> Red Hat
>>>
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
-------------- next part --------------
A non-text attachment was scrubbed...
Name: OpenPGP_signature
Type: application/pgp-signature
Size: 840 bytes
Desc: OpenPGP digital signature
URL: <https://lists.freedesktop.org/archives/dri-devel/attachments/20220418/47e4a494/attachment.sig>