device probe re-tried for failed isa device

[Matthew N. Dodd]

On Fri, 13 Jan 2006, Norbert Koch wrote:
> 4. A_probe(unit 1)
>  <-- fails with ENXIO because hardware is not present

Your IDENTIFY method allows device enumeration.  You should not create 
devices in IDENTIFY that do not exist.

Consider use /boot/device.hints add ISA devices.  An IDENTIFY method for 
ISA devices is only useful if there is some programatic method for 
identifying their presence in the system.  Look at the ISA frontends 
for ex(4) and ep(4) for an example of a proper IDENTIFY method.

> Is it correct to initialize softc in identify()?

No.  IDENTIFY only adds the devices.  The association with the driver 
takes place after PROBE.