Re: [PATCH v4 4/5] fbdev: Split frame buffer support in FB and FB_CORE symbols

[Javier Martinez Canillas]

Hello Andy,

Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> writes:

> On Tue, Jul 04, 2023 at 01:05:28AM +0200, Javier Martinez Canillas wrote:
>> Currently the CONFIG_FB option has to be enabled even if no legacy fbdev
>> drivers are needed (e.g: only to have support for framebuffer consoles).
>> 
>> The DRM subsystem has a fbdev emulation layer, but depends on CONFIG_FB
>> and so it can only be enabled if that dependency is enabled as well.
>> 
>> That means fbdev drivers have to be explicitly disabled if users want to
>> enable CONFIG_FB, only to use fbcon and/or the DRM fbdev emulation layer.
>> 
>> This patch introduces a non-visible CONFIG_FB_CORE symbol that could be
>> enabled just to have core support needed for CONFIG_DRM_FBDEV_EMULATION,
>> allowing CONFIG_FB to be disabled (and automatically disabling all the
>> fbdev drivers).
>> 
>> Nothing from fb_backlight.o and fbmon.o is used by the DRM fbdev emulation
>> layer so these two objects can be compiled out when CONFIG_FB is disabled.
>
> ...
>
> Wondering if
>
>   if FB_CORE
>   ...
>   endif
>
> makes Kconfig looking better instead of replacing all these "depends on" lines.
>

Yes, I discussed that with Arnd and he said that the if / endif is just
syntax sugar so I didn't do that change to keep the patches simpler. But
is something that you could change as a follow-up if you prefer that way.

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat