Re: Generic Kernel API

On Wed, 9 Nov 2005, Marcin Jessa wrote:

> Sure, but the point is to use native FreeBSD drivers, even if they were 
> in closed source binary form and not drivers written for an entirely 
> different O.S.

I think there is general agreement that it would be nice to be able to 
offer both relatively static APIs and ABIs to device driver writers 
writing device drivers for FreeBSD.  However, with the massive changes in 
kernel architecture over the last 4-5 years as part of SMPng and the 
threading work, that simply hasn't been possible.  We do attempt to keep 
the API and ABI for device drivers relatively stable over the lifetime of 
a major release (i.e., 4.*, 5.*, 6.*) but even that runs into occasional 
problems.  My hope is that in the next year or so, things will settle down 
significantly as we begin to flush the last of the non-MPSAFE drivers from 
the system, and reach a point where all device drivers can use consistent 
synchronization.  Among other things, we have an item scheduled for the 
FreeBSD developer summit at EuroBSDCon to nail down parts of the network 
device driver API for this purpose.  I.e., there is interest in what has 
been proposed, but we're not quite at a point where we can nail down the 
API in a more permanent way.

Robert N M Watson