Re: Firmware versioning best practices II

[David Woodhouse <dwmw2@infradead.org>]

On Fri, 2010-02-19 at 18:23 -0800, Luis R. Rodriguez wrote:
> Last year, with the help of the community we at Atheros opened up the
> first (to my knowledge) firmware for a device driver used on the Linux
> kernel. The community has been advancing the firmware and making
> changes and even an alternative driver with more features is being
> baked. We hadn't dealt with open firmware before and this itself
> raises a few management questions about the firmware APIs, code
> revision and general best practices which are likely not documented
> anywhere. We reviewed this on linux-wireless last year [1] and Pavel
> Roskin made a good suggestion for model to follow. I still have a few
> more questions though and wanted a wider review on this.
> 
> I've documented a summary of what we have discussed and suggested so far here:
> 
> http://wireless.kernel.org/en/developers/Documentation/firmware-versioning
> 
> We should still address how drivers should deprecate firmware. Can we
> deprecate old firmware APIs from drivers on each kernel release? Any
> other comments or feedback?
> 
> [1] http://wireless.kernel.org/en/developers/Documentation/firmware-versioning
> 
>   Luis

So far it looks like you've just rewritten a subset of the rules for
handling shared library sonames.

I wouldn't suggest that including the API version as a _separate_ field
from the code version is best practice. Why not just bump the major # of
the code version when you change the API, just as we do with shared
libraries?

That doesn't prevent some people from using foo-$APIVER-$CODEVER if they
really have to, of course -- if they have firmware which can be
conditionally compiled for both old and new APIs, for example. But I
don't think it should be recommended.

-- 
David Woodhouse                            Open Source Technology Centre
David.Woodhouse@intel.com                              Intel Corporation