Re: [PATCH] ARM: dts: add "simple-bus" to "arm, amba-bus" compatible nodes

[Masahiro Yamada]

Hi Rob, Mark, Jon,


Setting aside the future plan, anyway we should avoid
relying on an undocumented compatible string.
(and we should avoid its spread as Rob pointed out.)

I rephrase the git-log  (no update in the code-diff).

Could you check v2, please?
https://patchwork.kernel.org/patch/8529701/

Better?





2016-03-04 5:23 GMT+09:00 Rob Herring <robh+dt@xxxxxxxxxx>:
> On Thu, Mar 3, 2016 at 4:12 AM, Jon Medhurst (Tixy) <tixy@xxxxxxxxxx> wrote:
>> On Thu, 2016-03-03 at 12:07 +0900, Masahiro Yamada wrote:
>> [...]
>>> This patch is derived from Rob Herring' comment
>>> "BTW, we should also kill off "amba-bus" which is an ambiguous term"
>>> in the following thread:
>>> http://lkml.iu.edu/hypermail/linux/kernel/1601.0/01822.html
>>>
>>>
>>> So, the plan would be like this:
>>>
>>> [1] Make device trees not depend on "arm,amba-bus"   (this commit)
>>> [2] New device trees should no longer use "arm,amba-bus" alone.
>>> [3] Go though some releases until we do not care about the backward
>>> compatibility
>>
>> Why would we stop caring about backwards compatibility? If I was a user
>> of any of the platforms in question and updated my kernel, I wouldn't
>> expect to have to debug why it was broken, then install a new dtb to fix
>> it - which may be a tricky thing to do, depending on the firmware used
>> to boot Linux.
>
> If no one notices, then there is no ABI. Things break all the time
> when nobody cares. It will be more than a few releases for sure. We
> may never get to step 3, but we should do step 1 so people stop
> copy-n-pasting this in step 2.
>
> Rob
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-- 
Best Regards
Masahiro Yamada