[opensolaris-summit] driver limits [was Re: My comments (very subjective) on proposed Summit topics]

[Alan DuBoff]

On Wed, 26 Sep 2007, James Carlson wrote:

> Alan DuBoff writes:
>> I know you do, and I believe your intentions are quite good. As a case in
>> point, I know you try to follow the DDI strictly. Sun internal drivers
>> seem to have been some of the worst offenders of sticking to the DDI.
>
> You seem to say that as though it were a bad thing.

Not a bad thing directly, but if Sun creates and advocates that driver 
writers adhere to the DDI, but doesn't do it them self, it's a kind of 
double speak.

> So, case in point, the GLDv3/Nemo interfaces are not part of the DDI.
> Many of our drivers use them anyway.  If someone proposed to add a new
> Ethernet driver to ON, and that driver used only DDI interfaces (thus
> ignoring Nemo), I would certainly consider the driver to be defective.
>
> Thus, DDI isn't a mandate.

GLDv3 is an edge case right now as the interfaces are going to be public 
soon. Currently I am working with driver that was written to them, and it 
requires you copy/use mac.h and mac_ether.h from uts/common/sys/. This is 
only due to evolution of the development process. That was not what I was 
referring to in my post per se.

This is a valid case for using private interfaces, IMO.

It's not that using private interfaces is a bad thing, it's just that the 
driver stands the chance of breaking if those interfaces change. Any 
public interfaces are guaranteed to stay stable, I believe.

--

Alan DuBoff - Solaris x86 IHV/OEM Group