> > Wrong. You will only get a performance hit *if* there has been a
> > change to the internal kernel API's that necessitate a compatibility
> > layer to be implemented so the old drivers can still be used.
>
> And you'll carry that performance hit every time you make these
> changes.
Of course, but as you said below these changes happen very rarely
indeed.
> How much of this should we carry? Should Linux 3.4 still support
> the old PCI interfaces? If it did, it would be only to avoid
> losing some binary driver whose author/supplier was undoubtedly
> negligent.
Eventually there comes a time when you can remove the old interfaces
when they are no longer desirable for maintanance reasons.
> The Linux device driver interfaces (such as they are) are fairly
> stable indeed. The higher-level interfaces (for filesystems, for
> example) are a lot more mobile, but this isn't your issue.
>
> The fact is that stable kernels have a fairly static driver
> interface, which is _almost always_ source-compatible, if not
> binary-compatible.
Exactly! If the interfaces really are very stable and hardly ever
change, then what the hell is all the fuss about actually *defining*
what the currently API's are so that binary compatibility can be
assured?
Regards,
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+---------------------------------------------------------------+
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