[Ksummit-2013-discuss] ARM topic: Is DT on ARM the solution, or is there something better?

[Richard Cochran]

On Wed, Oct 23, 2013 at 11:49:04AM +0200, Thierry Reding wrote:
> 
> If a runtime warning isn't good enough, we can easily add a Kconfig
> option too. If people want to test-drive new functionality and accept
> that they might have to update the DTB even on a regular basis, they
> could activate that option and use all supported devices, even those
> with experimental bindings. Such an option could default to n, upon
> which the OF core just wouldn't match anything that carries the
> experimental marker.
> 
> Does that sound like a good compromise?

I think having a printk warning would be pointless because if the
majority of ARM bindings are unstable as you say, then the average
system will emit tons of them, encouraging people to just ignore them.

A kconfig option to allow unstable bindings seems okay to me in
principle, as long as progress toward getting stable bindings
continues. However, I expect that this option would become a "sticky
bit" that is just left on forever (remember CONFIG_EXPERIMENTAL?).
There would be little motivation for developers to ever get bindings
into the "stable" category.

I still don't understand why someone (linario?) can't host an
arm-dt-devel tree that allows the freedom to change bindings and
features the best source for supporting the latest ARM SoCs. I don't
buy the argument that only Linus' tree gets enough testing. If another
tree really is the best ARM tree, then it will get plenty of attention
and testing. Other people do this (for example, the TI arago tree),
apparently with good success.

Thanks,
Richard