Migrating XO-1.75 to device tree - upgrade considerations

[Martin Langhoff]

On Tue, Aug 21, 2012 at 7:24 PM, James Cameron <quozl at laptop.org> wrote:
> On Tue, Aug 21, 2012 at 12:04:04PM -0600, Daniel Drake wrote:
>> 2. Append the XO-1.75 device tree to the kernel image.
>
> We also hope to boot this same kernel on other hardware, so it might
> be necessary to include multiple device trees in this kernel.

While that is a valid consideration, it is not a foregone conclusion
that we'll ship a single image for XO-1.75 and XO-4.

TBH, I think it is a laudable, elegant goal, but the practicalities of
getting XO-4 into production mean we have to consider very carefully
whether we want to have the freedom that a separate build provides.

> We might also version the device trees, so that "good" is easier to
> define.

Yes, please. As others have pointed out in internal communications,
"best, accepted practice" in DT layout is likely to change over time.
At least we can say: it is early days, and DT practices haven't
settled yet.

We have to have a means to version our DT, and perhaps ship a "DT I
understand" with each kernel, as a fallback.

cheers,




m
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