Re: Address of second TMSCP controller

[David Brownlee <abs%netbsd.org@localhost>]

On Fri, 29 Jan 2021 at 14:17, Mark Pizzolato - Info Comm
<Mark%infocomm.com@localhost> wrote:
>
> [... floating address assignment discussion ...]
>
> VMS essentially requires that this algorithm is used to assign device addresses.
>
> The complete details of this process are implemented in the simh VAX and PDP11
> Simulators in the routine auto_config in module PDP11/pdp11_io_lib.c.
> A distinctly lesser cut at this is implemented in the simtools repository config11/config11.c
> module.
>
> Given the decades of legacy behavior where device addresses are explicitly declared
> in BSD configurations, it would seem quite late in the day to think about changing
> how things have always worked for BSD.

Things are always changing, and busses behave differently - even
nominally the same bus (I2C) can have to have device probe and
attachment handled differently depending on differences in hardware
implementation.

I think it would be reasonable for the uba bus in NetBSD to have an
option to follow floating address assignment rules when probing for
devices - it could probe for any defined devices without explicit csr
addresses using the floating algorithm, and then try to attach any
devices with csrs as a second pass.

Of course, this is all assuming someone wanted to write the code :-p

David