On Fri, Nov 29, 2013 at 09:42:23AM -0800, Greg KH wrote: > On Fri, Nov 29, 2013 at 10:37:14AM +0100, Thierry Reding wrote: > > > > Some of this is a consequence of the push to have the firmware > > > > minimal. As soon as you say the kernel has to configure the address > > > > map you've created a big complexity for it.. > > > > > > Why the push to make firmware "minimal"? What is that "saving"? You > > > just push the complexity from one place to the other, just because ARM > > > doesn't seem to have good firmware engineers, doesn't mean they should > > > punish their kernel developers :) > > > > In my experience the biggest problem here is that people working on > > upstream kernels and therefore confronted with these issues are seldom > > able to track the latest developments of new chips. > > > > When the time comes to upstream support, most of the functionality has > > been implemented downstream already, so it actually works and there's no > > apparent reason why things should change. > > That's a failure of the companies involved. Yes, I know. > > Now I know that that's not an ideal situation and upstreaming should > > start a whole lot earlier, but even if that were the case, once the > > silicon tapes out there's not a whole lot you can do about it anymore. > > Starting with upstreaming even before that would have to be a solution, > > but I don't think that's realistic at the current pace of development. > > For other companies it is realistic. I have a whole presentation on > this, and why it even makes good business sense to do it properly (hint, > saves you time and money, who doesn't like that?) I've seen a recording of that presentation. Twice. =) > > There's a large gap between how fast new SoCs are supposed to tape out > > and the rate at which new code can be merged upstream. Perhaps some of > > that could be mitigated by putting more of the complexity into firmware > > and that's already happening to some degree for ARMv8. But I suspect > > there's a limit to what you can hide away in firmware while at the same > > time giving the kernel enough information to do the right thing. > > > > I am completely convinced that our goal should be to do upstreaming > > early and ideally there shouldn't be any downstream development in the > > first place. The reason why we're not there yet is because it isn't > > practical to do so currently, so I'm very interested in suggestions or > > finding ways to improve the situation. > > "Practical"? Heh, other companies know how to do this properly, and > because of that, they will succeed, sorry. > > It can be done, the fact that ARM and it's licensees don't want to do > it, doesn't mean it isn't "practical" at all, it's just a failure on > their part to do things in the "correct" way, wasting time and money in > the process. Well, I can't really argue with that, so I'll stop with the whining and go back to work. Thierry
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