Re: New kernel/resource.c

Alon Ziv (alonz@cs.Technion.AC.IL)
Wed, 14 Jul 1999 22:51:23 +0300 (IDT)


On Wed, 14 Jul 1999, David Hinds wrote:
>
> Thinking about it some more, the only way I see to handle all the
> problem cases I can think of, is to have two separate resource trees
> for each type of resource, one for driver ownership, and one for
> hardware routing, rather than one unified tree. So we'd have two
> trees like:
>
[...deleted...]
>
> This avoids the problem of defining a new API for passing resource
> information to device drivers: they can just manipulate the driver
> resource trees. The hardware tree will be populated by bus drivers:
> the PCI subsystem, PnP, PCMCIA/CardBus, etc.
>

One problem still remains: that of telling the driver which physical
device(s) it should control. And, a related problem, telling this to an
already loaded driver (for hotplug &c).

It seems like we'll _have_ to introduce another initialization call to
hotplug capable drivers, to inform them of the actual hardware they're
controlling. One idea I had about it was that such drivers won't connect
to the hardware in their `old-style' init function, but instead invoke
some registration function (e.g., register_pci_driver()) to tell the
system what hardware they support. The bus drivers will then invoke
configuration calls on the driver and give it a list of pointers to
resource records which belong to its hardware.

BTW, with all this talk about hotplug and such, I haven't seen any
suggestions for solving the problem of persistently mapping the physical
hardware to logical device numbers; we need some way to have the system
allocate the same major/minor number to the same hardware whenever it's
used... Any ideas?

-az

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