On 07/16/2013 07:50 PM, Rob Herring wrote: > On Tue, Jul 16, 2013 at 6:30 PM, Stephen Warren <swar...@wwwdotorg.org> wrote: >> On 07/15/2013 05:02 PM, Stephen Warren wrote: >>> On 07/15/2013 01:34 PM, Rob Herring wrote: >>>> On 07/15/2013 01:40 PM, Stephen Warren wrote: >>>>> From: Stephen Warren <swar...@nvidia.com> >>>>> >>>>> This property is no longer required by the GPIO binding. Remove it. >>>> >>>> Won't this break compatibility with older kernel? It is one thing to >>>> deprecate, but removal is another. If the relevant maintainers don't >>>> care, then I guess it is fine. >>> >>> Yes. >>> >>> I had originally hoped this could sneak in late for 3.11, but I suppose >>> it's too late now. vf610.dtsi is a new file in 3.11 so has no legacy to >>> protect. >>> >>> Admittedly, the #gpio-cells property was added into the SPEAr files in 3.10. >> >> One more thought here: >> >> I know DT bindings are supposed to evolve so that a new kernel will >> support arbitrary old DTs. I'll call that backwards-compatibility for >> the DT parsing code. > > That is the more common case. > >> However, this situation is the reverse; this patch would prevent a new >> DT running on an older kernel. I'll call that forwards-compatibility. >> I'm not sure if the intent is to support this or not? It's certainly the >> first I explicitly thought about compatibility in this direction... > > So you would be okay if your computer stopped booting a kernel after a > BIOS update? It's the same deal. It's both forwards and backwards > compatibility that is needed.
I would strongly hope the BIOS/bootloader/... would have nothing to do with the DT content. There's a reason that Grant asserted early on that DTBs shouldn't be part of the BIOS/bootloader, but rather stored separately, so the DTB could be updated without updating firmware, just like the kernel. And I see no real problem with a new DTB requiring a new kernel or even vice-versa to be honest. _______________________________________________ devicetree-discuss mailing list devicetree-discuss@lists.ozlabs.org https://lists.ozlabs.org/listinfo/devicetree-discuss