Subject: Re: [PATCH] powerpc: document new interrupt-array property

From: Segher Boessenkool <[email-masked]>
Date: Tue, 27 Feb 2007 03:52:41 +0100

>> And if a program parsing the device tree sees no valid
>> "interrupts" property, it can validly assume the device
>> doesn't have interrupts.
>>
>> Same problem.
>
> Sort of.  But the probable consequences of mistakenly believing a
> device has no interrupts are substantially less messy than mistakenly
> believing you understand the node's interrupts when you don't.

"Less messy"...  well the device won't work properly
in either case.  The kernel might completely screw
up programming the interrupts, which would mean it
doesn't do enough sanity checking; or it could give
spectacular oopses, where the "less messy" case would
simply be a device driver not running for your device.

If the one case gives you more information to track
down the problem than the other case, I argue that's
a shortcoming of the kernel, not of the OF binding.

Anyway, it's all a question of deployment: you just
have to make sure your users use a new enough kernel
with your device tree (and device), which you have
to do *anyway*.  Also DTS files are still conveniently
shipped with the kernel so it's even less of a problem.

Segher