[PATCH] Air isn't special

[Dirk Hohndel]

On Sun, Jun 01, 2014 at 09:55:04AM -0700, Linus Torvalds wrote:
> On Jun 1, 2014 9:34 AM, "Henrik Brautaset Aronsen" <
> subsurface at henrik.synth.no> wrote:
> >
> > The only places we need to treat air specially is:
> 
> No. You kind of proceed my point, by missing one of the cases I explicitly
> listed.
> 
> It's also special for the "do I have a tank at all", which sadly git messed
> up by the stupid and wrong default tank size handling, which was then
> messed up even further by the special "unused cylinder" logic that now has
> a configuration flag too.
> 
> So sadly, the while unused tank logic is terminally broken anyway, but it
> *used* to be sensible.

So let's talk about a sane design how we should handle the default tank
size and the unused cylinder thing.

I introduced both of those in response to feature requests and real issues
with dive computers sending us all gases that were configured, even if
they weren't used in a dive (I don't think you have a computer that does
that). 

I'm totally open to fixing what's broken there.

> It's also special for the d default has mix to be used for new tasks. Yadda
> yadda.
> 
> But whatever. I'm not going to bother arguing about it. You can mess things
> up all you want, it's not like it's my project.

Relax. The reason I poked you is because I still consider you very
important to this project. So instead of throwing a tantrum and then
sitting in the corner and not playing with the other kids, help us make it
better. You will have noticed that while I played with Henrik's change I
ended up not pushing it because, as you so kindly point out, it does break
quite a few things.

So as the current maintainer, here's my position:

a) I don't think we can easily get rid of air being special. There are
several cases where this really is the case and I grudgingly agree that
Linus has proven to me repeatedly in the past that making air special
makes the code simpler and more robust.

b) If someone comes up with a clean and simple way that addresses all
these corner cases, I'd love to get rid of air being special :-)

c) I'd really like to do better regarding that whole stupid "cylinder
used" and "default cylinder" mess. What we have is what I have gotten up
with to address the feature request / issues encountered. It seems to
mostly work but I'm all eager to hear about better solutions. Either in
prose or as patch :-)

Thanks

/D