[PATCH 1/1] Squashed 'dts/upstream/' changes from b35b9bd1d4ee..7e08733c96c8

[Sumit Garg]

Hi Jonas,

On Wed, 15 May 2024 at 13:11, Jonas Karlman <jonas at kwiboo.se> wrote:
>
> Hi Tom,
>
> On 2024-05-14 18:42, Tom Rini wrote:>
> > git-subtree-dir: dts/upstream
> > git-subtree-split: 7e08733c96c84eb323f47e9b248c924e2ac6272a
> > ---
> > This moves OF_UPSTREAM to be tracking the v6.9 release and is for the
> > -next branch. To test these changes yourself locally, either use my
> > "WIP/14May2024-next" branch or run:
> > ./dts/update-dts-subtree.sh pull v6.9-dts
> > yourself locally. I intend to wait a few days to apply this to -next, to
> > give people time to test.
> >
>
> There are currently more boards/SoCs that use OF_UPSTREAM in master
> branch than in next branch, a few Rockchip SoCs and other boards/SoCs.

Glad to see more OF_UPSTREAM adoption.

> Next dts/upstream sync will probably be good to do together with a merge
> of master into next :-)

I don't have any particular opinion here and rather leave it upto Tom
how he would like to merge stuff.

>
> Also what is the expected sync cadence of dts/upstream? Linux v6.10 will
> probably be released shortly after U-Boot v2024.07. So will next sync be
> to v6.10-dts if that happens in the U-Boot merge window or do we expect
> 2024.10 to use v6.9 DTs if the v6.10 release gets delayed and miss the
> U-Boot merge window?
>
> Linux kernel typically have all major DT changes in -rc1 and fixes in
> later -rcX, so for next branch I would suggest an early sync to a
> v6.10-rcX-dts tag, and then sync to the final v6.10-dts tag once v6.10
> gets released. That should give more time for testing, migration and
> cleanup using v6.10 DTs in time for a 2024.10 release.

I can see the reasoning for an aggressive DT syncing approach, it has
been brought up in the past too. And the major reason for the current
moderate sync approach [1] is to limit any DT ABI breakages for
U-Boot, we are even prone to breakages with syncs against major Linux
kernel releases (eg. v6.10-dts etc.). It has been a long time
discussion topic where we have been advocating about requirements for
DT ABI stability [2].

So having DT syncs done during the merge window will shorten the
testing window for developers/maintainers. And more syncs means a
multiplicative factor for testing. However, time will tell with more
and more platforms adopting OF_UPSTREAM, if there are any real DT ABI
breakages seen in the future. But surely if they are very rare then I
am open to adopting aggressive DT sync approaches.

[1] https://docs.u-boot.org/en/latest/develop/devicetree/control.html#resyncing-with-devicetree-rebasing
[2] https://www.mail-archive.com/boot-architecture@lists.linaro.org/msg02162.html

-Sumit

>
> Regards,
> Jonas