Re: [PATCH 1/6] MIPS: Ingenic: Fix inverted MIPS_NO_APPENDED_DTB logic in Kconfig

[H. Nikolaus Schaller]

Hi Paul,

> Am 26.10.2026 um 00:41 schrieb Paul Cercueil <paul@xxxxxxxxxxxxxxx>:
> 
> The original code is not an 'unintended behaviour', it works as it was
> designed to work: if the kernel is not configured for an appended DTB,
> then a DTB should be built-in. This is because on Ingenic SoCs at
> least, at the time this code was written no bootloader was passing the
> DTB to the kernel.
> 
> I understand your usecase (which is very reasonnable) but this fix as-
> is only fixes things for you, while breaking every other board.
> 
> I'd suggest to fix it by adding a proper description to BUILTIN_DTB (so
> that it can be selected from the UI or a defconfig), then update all
> arch/mips/configs/ for Ingenic based boards to enable
> CONFIG_BUILTIN_DTB=y unless they rely on the appended DTB
> functionality. Then this "select BUILTIN_DTB if MIPS_NO_APPENDED_DTB"
> Kconfig dependency can be retired.

Thank you for the detailed feedback and for explaining the historical
background. That makes perfect sense.

I will follow your suggestion and add split this in a V2 patch series so that:
- Adds a proper prompt/description to BUILTIN_DTB so it becomes user-selectable
- Update the existing Ingenic defconfigs to explicitly enable CONFIG_BUILTIN_DTB=y
  where needed (I think there are just 4 cases)
- Remove the automatic select BUILTIN_DTB if MIPS_NO_APPENDED_DTB from MACH_INGENIC.

This should cleanly support my (and likely other's) use case of a
bootloader-provided DTB without breaking any existing board.

BTW: we have this working with U-Boot on CI20 as well. So a generic ingenic
kernel and all board specific cases in the DTB.

I'll update and also consider the feedback from Sashiko-bot and others for
the other patches in this series.

BR and thanks,
Nikolaus