[U-Boot] [PATCH v2 3/5] sunxi: DT: A64: update device tree file for Allwinner A64 SoC

[Maxime Ripard]

On Wed, Oct 17, 2018 at 04:18:41PM +0100, Andre Przywara wrote:
> On Tue, 16 Oct 2018 22:09:30 -0700
> Vasily Khoruzhick <anarsoul at gmail.com> wrote:
> 
> Hi,
> 
> > Updates the device tree file from the the Linux tree as of v4.19-rc4,
> > exactly Linux commit:
> 
> Does this work easily without syncing the .dts files as well?
> 
> > commit 7876320f8880 (tag: v4.19-rc4)
> > Author: Linus Torvalds <torvalds at linux-foundation.org>
> > Date:   Sun Sep 16 11:52:37 2018 -0700
> > 
> >     Linux 4.19-rc4
> 
> So this sounds like the right thing to do, but in this particular case
> breaks Ethernet with UEFI booting in all distribution installers or
> kernels out there (except >= Linux 4.19-rc1).
> I consider this a major use case of U-Boot's DTB, so what do we do
> about this?
> The reason is that we dropped the "syscon" compatible string at the end
> of the system-controller node, which older kernels rely on to find the
> syscon node.
> I suggested to re-add this[1], but didn't have much success,
> unfortunately.
> The easiest would be to re-add (or not remove) "syscon" for U-Boot's
> copy, but this would mean a deviation from the Linux DT's. I am fine
> with this, but would like to hear more opinions.

tl; dr: You want to build something robust on top of assumptions that
have never been guaranteed. I'm fine with having it as a U-Boot
addition, if it's what it takes.

Maxime

-- 
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com