Re: 10.0_RC5 at boot on VAX 4000/200

> Netbooting I saw:

> [   1.0000000] ubasearch: calling config_probe
> [   1.0000000] udamatch: tries=0, mi_iot=80335a78, mi_iph=8afeb468
> [   1.0000000] udamatch: mscp_waitstep 1
> [   1.0000000] mscp_waitstep: read_val=00000800, result=00000800, status=1

> Booting from disk I saw:

> [   1.0000000] ubasearch: calling config_probe
> [   1.0000000] udamatch: tries=0, mi_iot=80335a78, mi_iph=8afeb468
> [   1.0000000] udamatch: mscp_waitstep 1
> [   1.0000000] mscp_waitstep: read_val=00000000, result=00000800, status=0

> The all-zeros read value leads to the board not being recognised but I've go$

I'd guess it's an MSCP protocol issue.

At this point, I'd say, anyone trying to debug this further should read
the MSCP spec.  It has some rather bizarre things that you will
probably need to know.

Since I haven't read the NetBSD code in question, I don't know whether
any of them are relevant, but there is at least one register (I can't
recall its name offhand) that returns one value when starting
initialization but a different value when running.  I would expect the
uda driver to handle that correctly - it seems to do so in 1.4T - but
perhaps that code has bitrotted since then, or perhaps there's another
such register I don't recall...or my guesses could be completely wrong.
But having a copy of the MSCP manual at hand is likely to be helpful.

I have transcriptions of AA-L619A-TK and AA-L621A-TK in
/mouse/docs/DEC/ on ftp.rodents-montreal.org (accessible by HTTP as
well as FTP, for pointy-clicky convenience).  They were my major
references when writing my MicroVAX-II emulator's MSCP emulation.

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