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driver interface stability

driver interface stability

Posted Jul 23, 2004 22:55 UTC (Fri) by giraffedata (subscriber, #1954)
In reply to: driver interface stability by elanthis
Parent article: Kernel Summit: The customer panel

So I think you're saying that including a device driver in the Linux kernel solves the problem of future API changes, but doesn't solve the problem of past API changes. I.e. a device vendor who ships a driver for today's Linux would be shielded from any incompatibility with tomorrow's Linux, but there still wouldn't be any drivers for yesterday's Linux.

People usually think of the API problem as being one of future API changes, since there's nothing a device vendor can do about those, whereas the vendor could, if he really wanted to, ship drivers for past versions of the API.

But I suppose the fact that vendors don't take the trouble to ship drivers that work with all historical Linuxes is also a good reason never to change (incompatibly) the API.


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driver interface stability

Posted Jul 27, 2004 13:53 UTC (Tue) by mdomsch (subscriber, #5920) [Link]

> But I suppose the fact that vendors don't take the trouble
> to ship drivers that work with all historical Linuxes is
> also a good reason never to change (incompatibly) the API.
Hardly. That would suggest that because people outside our sphere of influence (they're not in the kernel) don't do work with the kernel, that they should have significant influence on kernel design and development (freezing the APIs). That way lies madness. The kernel (through kcompat.h) and projects like DKMS make it easier for vendors to backport their work to earlier kernels, even those with different APIs than the current kernels. Also, it's a matter of timing. If drivers are merged in early enough, then there's less need to do backports, yes? That can't always happen (new hardware does become available, and users of that hardware want support on historical kernels), so good programming practices like kcompat.h and DKMS can help vendors there too.


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