How to met the dependency when the kernel configuration items "CONFIG_FB_INTEL" and "CONFIG_DRM_I915" have the value of 'm'?

[You-Sheng Yang]

On Fri, Aug 19, 2022 at 7:53 PM 孙滢 <sunying at nj.iscas.ac.cn> wrote:
>
> Hi,
> According to the definition of the configuration item "CONFIG_FB_INTEL" in the Kconfig file, there is:
>
> config FB_INTEL
>   depends on !DRM_I915
>
> You can see that these two configuration items have a reverse dependency.
> However, in many versions of Ubuntu, these two configuration items take the value 'm', and 'm' is generally treated as true in the depends condition. So it looks like the dependency is not met?

https://docs.kernel.org/kbuild/kconfig-language.html#menu-dependencies
It's not. !DRM_I915 means `2 - DRM_I915`, which is 1 if DRM_I915
equals 'm', or 2 if DRM_I915 equals 0.

-- 
Regards,
You-Sheng Yang