Re: [PATCH]"drm: change DRM_MIPI_DSI module type from "bool" to "tristate".

[Emil Velikov]

On 11 October 2016 at 10:33, Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx> wrote:
> On Tue, 11 Oct 2016, "Sun, Jing A" <jing.a.sun@xxxxxxxxx> wrote:
>> It's needed that DRM Driver module could be removed and reloaded after
>> kernel booting on the projects that I have been working on, and I hope
>> such module type change could be accepted. Looks like Iwai has similar
>> change request as well. Would you please review it and let us know if
>> any concerns?
>
> Looking at the Kconfig, selecting CONFIG_DRM_MIPI_DSI is against the
> recommendations of Documentation/kbuild/kconfig-language.txt:
>
>         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.
>
> Indeed, you may end up with CONFIG_DRM_MIPI_DSI=y and CONFIG_DRM=m,
> which violates DRM_MIPI_DSI dependency on CONFIG_DRM. This is broken and
> should be fixed. The suggested patch does *not* fix this issue.
>
Jani, git log suggests you as the unfortunate author of the select
DRM_MIPI_DSI/select DRM_PANEL hunks in i915 ;-)

>From a cutesy skim through panel/ there are a handful of things to
squash - unused select/depend on, s/select/depend on/ etc. Sadly I
don't have the time to address these :-\

Regards,
Emil