Re: multiple drivers, single device (was Re: Announce: Linux-next(Or Andrew's dream :-)))

[Linus Torvalds]

On Tue, 12 Feb 2008, Jeff Garzik wrote:

> Greg KH wrote:
> > The work I'm doing here is for stupid PCI firmware engineers, who have
> > created devices that are different things, all bound up under the same
> > PCI device.  I'm thinking of watchdog timers and random number
> > generator and i2c controller on the same PCI device, or even the more
> > basic, frame buffer and DRM access to the same PCI video device.
> 
> Yes, that has a known solution:  have your driver register i2c, rng, watchdog,
> etc. functions.
> 
> Works just fine inside today's infrastructure, no changes needed.

Indeed. If you have a multi-function device that shows up as a single PCI 
function, just make it have its own "private bus", and make it show up as 
a "devices within a device".

Create the fake PCI subdevices that have no "real" counterpart, except as 
parts of the stupid device that couldn't be bothered to be seen as 
multiple _real_ functions.

That not only solves the infrastructure issues, it's actually The Truth 
with capital letters. It is, after all, how the device actually works 
internally.

			Linus
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