Re: Aw: Re: [PATCH] arm64: dts: mediatek: Apply all DT overlays at build time

From: AngeloGioacchino Del Regno

Date: Wed Nov 19 2025 - 03:39:10 EST


Il 18/11/25 18:02, Frank Wunderlich ha scritto:
Hi,

this looks similar to my attempt i did here

https://patchwork.kernel.org/project/linux-mediatek/patch/20240608080530.9436-2-linux@xxxxxxxxx/

But in my case i added full dtb with 2 overlays as there can be 2 devices (1 mmc + 1 spi) at one time.
So usable as dtb for bootloader config without overlays, not only for validation...


Please don't top post :-)

That said, for the target of what is done here, I think yours is nicer to the eye
compared to Rob's (not his fault at all, most of the times overlays cannot be
applied together, he can't possibly know if that is possible in this case).

If there is really no other solution to that... well, at this point I prefer to
have something nicer to the eye, with all of the necessary "evil" that comes with
it.

P.S.: Strong words contained in this reply are meant to be lighter than they appear

Cheers,
Angelo

regards Frank


Gesendet: Dienstag, 18. November 2025 um 13:31
Von: "Rob Herring" <robh@xxxxxxxxxx>
An: "AngeloGioacchino Del Regno" <angelogioacchino.delregno@xxxxxxxxxxxxx>
CC: "Matthias Brugger" <matthias.bgg@xxxxxxxxx>, "Krzysztof Kozlowski" <krzk+dt@xxxxxxxxxx>, "Conor Dooley" <conor+dt@xxxxxxxxxx>, linux-kernel@xxxxxxxxxxxxxxx, linux-arm-kernel@xxxxxxxxxxxxxxxxxxx, linux-mediatek@xxxxxxxxxxxxxxxxxxx, devicetree@xxxxxxxxxxxxxxx
Betreff: Re: [PATCH] arm64: dts: mediatek: Apply all DT overlays at build time

On Tue, Nov 18, 2025 at 3:36 AM AngeloGioacchino Del Regno
<angelogioacchino.delregno@xxxxxxxxxxxxx> wrote:

Il 17/11/25 22:13, Rob Herring (Arm) ha scritto:
It's a requirement that DT overlays be applied at build time in order to
validate them as overlays are not validated on their own.

Add targets for all the Mediatek overlays.

Signed-off-by: Rob Herring (Arm) <robh@xxxxxxxxxx>
---
This will soon be a warning[1].

Note that if it is desired that the combined .dtb is not installed, then
the combined .dtb should be added to 'dtb-' variable instead.


Uhm, sorry, can't we do something such that we don't generate a DTB with a
preapplied overlay?

Even something like generating those and deleting before build finalization
could work, I guess, though that'd be hacky maybe.

I don't know if this is the case, but I'm worried that various people have
scripts to copy DTBs somewhere (in some partition) or embed those in images,
and if they get the preapplied overlay dtbs in the same place, havoc could
happen as the bootloaders might be selecting wrong dtbs (as a plus, there is
no dtbo that varies machine compatible strings, rightfully).

If they aren't using dtbs_install for that, then that is their
problem. When we moved all the arm32 DTs to vendor directories,
dtbs_install maintained the old structure which seemed sufficient to
not break folks. The same should apply here.

Rob