[PATCH] Do not send low level debugging to the modem

[Harald Welte]

On Tue, Mar 25, 2008 at 09:25:33AM -0300, Werner Almesberger wrote:
> Graeme Gregory wrote:
> > I think we finally have to make the decision is GTA01 and GTA02
> > different kernels.
> 
> Yeah, I wonder if it's really worth the trouble to maintain binary
> compatibility. This decision predates my involvement in OpenMoko,
> but perhaps Harald or Mickey can explain.

Well, the number one reason is: Because there is no reason to have
different kernel images.  The ARM kernel (and the samsung SoC support in
it) have this excellent way of building a single kernel image with
suport for any number of devices based on the same architecture.

PowerPC also has something fairly similar in effect, even more
convoluted in the implementation, IIRC.

For looking at long-term support, it is definitely helpful to keep the
number of different images as minimal as possible.

TomTom, IIRC, are using 2410, 2440, 2443 and maybe even some other
samsung SoC, and they drive all of them from a single kernel.

You reduce the amount of images to be built, maintained, updated, reduce
confusion inside development, support and in the user community.

All that I've seen so far in conflict with a single kernel is the low
level UART debug code.  That code should not be there in production
builds, and is thus a non-issue.  Another idea would be to make that
low-level code non-static and somehow use the console that's passed on
the commandline (by having some global variable that indicates the UART
base, rather than having it compile time defined).

99.9% of the kernel can do it, and only some very small debug code
can't.  Using different kernel images will disregard all that working,
flexible code for one small debug hack that should not be enabled at
all.

-- 
- Harald Welte <laforge at openmoko.org>          	        http://openmoko.org/
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