Re: I/O bus reset to fix CMD MSCP controllers (and probably others)

> And now we're having these issues on NetBSD, too. I really wonder
> whether NetBSD might have done a I/O bus reset in the past that went
> missing during some refactoring or rototilling.

Data point: when I boot 1.4T under my emulator, I see only three I/O
resets.  One is the emulator resetting itself during startup.  The
other two are due to writes to IPR 55, which happen:

- Early in the ROM code (before terminal type detection starts).
- After the "b dua0" command but before the "2..1..0.." prints.

I do not see any others.  In particular, I do not see any at any point
between the ">> NetBSD/vax boot ... <<" line and the single-user shell
prompt.

Of course, I also do not know whether 1.4T works with the hardware in
question.  But it does indicate that, at one point some time ago,
NetBSD didn't do any explicit I/O resets in that code path.

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