Re: [PATCH 1/5] ARM: dts: ti: Enable overlays for all DTB files

[Kory Maincent <kory.maincent@bootlin.com>]

On Thu, 12 Feb 2026 21:16:05 -0600
Robert Nelson <robertcnelson@gmail.com> wrote:

> On Thu, Feb 12, 2026 at 4:19 PM Andreas Kemnade <andreas@kemnade.info> wrote:
> >
> > On Thu, 12 Feb 2026 17:55:43 +0100
> > "H. Nikolaus Schaller" <hns@goldelico.com> wrote:
> >  
> > > > Am 12.02.2026 um 17:47 schrieb Andreas Kemnade <andreas@kemnade.info>:
> > > >
> > > > On Thu, 12 Feb 2026 16:49:43 +0100
> > > > "H. Nikolaus Schaller" <hns@goldelico.com> wrote:
> > > >  
> > > >>> Am 12.02.2026 um 16:26 schrieb Kory Maincent (TI)
> > > >>> <kory.maincent@bootlin.com>:
> > > >>>
> > > >>> Allow overlays to be applied to any DTB. This adds around ~40% to the
> > > >>> total size of the DTB files on average.  
> > > >>
> > > >> Is this unconditionally enabled or can it be turned off by some
> > > >> CONFIG? We have our own defconfig so I would not worry if if is
> > > >> enabled in omap2plus_defconfig and disabled in ours.
> > > >>
> > > >> We have several devices where the boot loader can't handle overlays
> > > >> (never touch a working boot-loader :) So this seems to only contribute
> > > >> to build and load time without benefit.
> > > >>  
> > > > As long as you do not add overlays, the bootloader does not care. I
> > > > would like to simply carry around the 1-bit mmc overlay for one broken
> > > > board. That would help me. So I think there is a benefit but nobody
> > > > forces you to use it.  
> > >
> > > Well, it does not force to use the really good feature, but it forces to
> > > add ~40% more file size and some more compile time, if I understand it
> > > correctly. 
> > Compile time, hardly measurable even if you just do make dtbs.
> >
> > Size on disk:
> > a) if it lives around in a /boot partitions with kernels and initrams in it,
> >    then we are around 1% more space needed.
> >
> > b) if it has separate partitions maybe on some mtd: Looking around: GTA04
> >    has quite some headroom left. Usage is still <50% even with symbols
> >    enabled.
> >
> > But on the other no one else seems to enable that besides for devices with
> > open expansion boards carrying "hats". So overall, should we really be the
> > exception?  
> 
> Do we want to maybe transition like TI did for k3?
> 
> Start with board specific DTC_FLAGS flags for specific boards:
> 
> and then just enabling overlays by default :
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/arch/arm64/boot/dts/ti/Makefile?id=bca4146b1f66dbca07591bfd6ad695c699b5a093
> 
> If we do board-specific, all the "Beagle" related items can be auto
> enabled `-@`..

Yes, I will move on to this solution for now to avoid too many complaints about
the devicetree size increases.

Regards,
-- 
Köry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com