On Sat, 1 Dec 2007, Benjamin Herrenschmidt wrote:
>
> On Fri, 2007-11-30 at 16:11 -0600, T Ziomek wrote:
>>> Possibly, though you aren't supposed to leave EARLY_DEBUG enabled
>>> once you are done debugging :-)
>>
>> I'm probably not the only person that would turn it on when needed,
>> think
>> "well, no harm in leaving it on for the rest of my development, and it
>> might be handy; just turn it off when we're done".
>>
>> It's these kind of non-obvious but undocumented things that make a lot
>> of
>> OSS code a pain to work with for non-experts [1]. What's the harm in
>> giving folks a heads-up?
>
> There is no harm, I didn't say I wasn't going to document it, you do
> have a point there, I was just mentioning by the way, that leaving
> EARLY_DEBUG is generally not a good idea in production.
>
> One of the things that arhc/powerpc provides is the ability for you to
> have a single kernel image boot boards with different 4xx processors for
> example, or different fsl booke processors. You lose that if you leave
> early debug on as it usually contain hard coded addresses for a given
> board.
>
> This is typically useful if you have several revisions / versions of
> your product, which could use different processor revisions or even
> model, and want a single kernel image to support them.
Makes sense (my last PPC work was with arch/ppc, when arch/powerpc was
just getting started, and I'm not using PPCs at the moment).
Maybe the better comment to add for EARLY_DEBUG is to turn it off when
not of immediate concern?
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