When to burn those bridges

[Doug Rabson]

On Wed, 2003-09-10 at 23:39, John Baldwin wrote:
> On 10-Sep-2003 Doug Rabson wrote:
> > 
> > My feeling about that was always that the hostb driver provides
> > absolutely no added value in the system. When I was developing agp
> > originally, I just nuked it and kldloading agp.ko worked just fine.
> 
> I don't mind if hostb were to die, but it does serve somewhat of a
> purpose.  A dummy vga driver might also be useful with Warner's PCI
> power management stuff as well.

A long time ago, I was thinking about a scheme where newbus would detach
a driver which had attached to a device at a very low priority if a new
driver was added via kldload.

The way it might work is that a 'placeholder' driver like hostb would
mark the device with a flag, e.g. device_set_placeholder. When a new
driver is loaded, devices set as placeholders would be re-probed in
bus_generic_driver_added as well as devices with no drivers at all. If
the new driver probed with a higher value than the current placeholder
driver, in device_probe_and_attach, the old driver would be detached and
the new one attached.