PPC 405GPr support in linux 2.4.32

Eugene Surovegin ebs at ebshome.net
Fri Apr 28 05:04:58 EST 2006

On Thu, Apr 27, 2006 at 11:32:45AM -0700, Stephen Williams wrote:
> Eugene Surovegin wrote:
> > There are bigger problems with 4xx support in 2.4 mainline than just 
> > missing some chips support.
> > 
> > Some parts which are already in 2.4 (e.g. ethernet driver) are of 
> > non-production quality. 
> > 
> > I can imagine Marcelo agreeing to commit 405GPr/405EP support as this 
> > change shouldn't break anything, but this will not make 2.4 support 
> > really useful for real world deployments. I think we are stuck with 
> > maintaining our own 2.4 trees with backports from 2.6. This is what I 
> > do myself of all our products (and yeah, diff between stock 2.4.32 and 
> > my internal version has already grown quite big to be acceptable for 
> > 2.4 inclusion).
> > 
> Of course we are going to have to keep our own per-board trees.
> but the blatantly common stuff, like the core 405gpr support and
> certain drivers, might as well go in if the gatekeeper can be
> convinced. You and I both probably have huge drivers for custom
> devices hanging off our PPCs, with various hacks to squeeze extra
> performance out. These make our transition to 2.6 difficult, and
> surely we are not alone.

Well, personally, I don't migrate to 2.6 not because I have many custom 
drivers in my tree (if they are properly written, migration is 
relatively easy), but because 2.6 in my opinion isn't production 
ready, at least for architectures I work with. 2.6 is slower, bigger, 
is constantly being broken by huge amount of changes, etc. I spent 
enough time making 2.4 work on our hardware given limitations and 
requirements put on performance, resources etc. I just don't have time 
to go through this cycle again. And I'm not talking about PPC stuff, I 
mean mostly generic stuff - filesystems, scheduling, networking, etc.

> So 2.4 is going to be around for a while longer for us, so we might
> as well make an effort to keep the house in some sort of order. It
> serves no one to keep these fixes a secret:-)

They aren't secret, but I can understand the simple fact that 2.4 is 
closed for a new stuff, we might not like that (although I do, just 
look at the mess "stable" 2.6 is :).

There is a point in every piece of software life-cycle when you have 
to stop adding features. 2.4 is already at this point, and we should 
accept that.


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