Re: [PATCH 6/8] drm: decouple from CONFIG_FB

[Sam Ravnborg <sam@ravnborg.org>]

Hi Arnd.

On Fri, Apr 17, 2020 at 10:03:23PM +0200, Arnd Bergmann wrote:
> On Fri, Apr 17, 2020 at 6:50 PM Sam Ravnborg <sam@ravnborg.org> wrote:
> 
> >
> > So what this try to say is that we cannot have FB a module while DRM is
> > built-in (marked N in the above).
> 
> Correct
> 
> >
> > Could you explain in the changelog why this combination is not good.
> > (Or tell me if my analysis was flawed).
> 
> I agree in hindsight this was less obvious than I thought ;-)
> 
> Added this text to the changelog:
> 
> |  When CONFIG_FB is a loadable module, DRM_KMS_FB_HELPER cannot be
> | part of the built-in subsystem, so add dependency to ensure this
> | can only be enabled if the DRM module can successfully be linked.
> 
> and this comment in the Kconfig file:
> 
> @@ -112,7 +112,7 @@ config DRM_DEBUG_DP_MST_TOPOLOGY_REFS
>  config DRM_FBDEV_EMULATION
>         bool "Enable legacy fbdev support for your modesetting driver"
>         depends on DRM && FB
> -       depends on FB=y || DRM=m
> +       depends on FB=y || DRM=m # DRM_KMS_FB_HELPER links against FB
>         select DRM_KMS_HELPER
>         select DRM_KMS_FB_HELPER
>         default y
> 
> Let me know if you think those changes are sufficient
> 
> > With this fixed (assuming I am right):
> > Reviewed-by: Sam Ravnborg <sam@ravnborg.org>

Yes, that explains it nicely - thanks.
But unless Daniel decides otherwise we do not get it applied.
He was not too happy with it.

	Sam