Re: "adapter resource shortage"?

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Tue, Mar 05, 2013 at 08:38:21AM +0100, Hauke Fath wrote:
> 
> See e.g. PRs 26825, 30531, 36900. I am not aware of any substantial
> change in newer NetBSD releases, and at work, we have phased out all
> mpt(4) adapters in favour of amr(4) ones.

There are no amr(4) adapters manufactured any more.  They became mfi(4),
approximately.

At least that driver seems to have become fairly stable by now.

> My understanding is that most of the mass storage interface drivers in
> NetBSD are inherited from {Free,Open}BSD, and diverging kernel
> interfaces appear to make cross-pollination ever harder. A recent
> example would be lack of support for the Areca 188x SAS controllers.

This isn't really quite right.  The Areca drivers are not the same at
all -- and you wouldn't want the one that's in FreeBSD, because it is
one of of those drivers that handles three or four rather different,
though related, types of hardware by doing:

case TYPE_A:
 do stuff
 break;
case TYPE_B:
 do stuff
 break;
case TYPE_C:
 do stuff
 break;

In a few dozen functions all over the driver.

Our Areca driver is very stable and it performs well, but what it
needs is to grow support for the two newest kinds of adapters in
a *sensible* way -- not what the FreeBSD and Linux drivers do.  A
sensible way would be to turn it into two or three drivers, all
using a common core of routines for most stuff, but with their
own versions of the functions where FreeBSD has those awful switch
statements...

I do not have time to do this.  I can provide hardware and advice
to anyone who does want to do it, though.

Over time, there are actually less kinds of disk controllers out
there, I believe.  What we need to do a little better at is ensuring
that our support for the ones you can actually still buy is solid and
performs well.

Thor