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Date:      Tue, 16 Sep 2014 20:00:58 -0700
From:      Mark Millard <markmi@dsl-only.net>
To:        freebsd-ppc@freebsd.org, Justin Hibbits <chmeeedalf@gmail.com>
Subject:   Re: PowerMac G5 boot hangups before Copyright notice: "Stopped at 0: illegal instruction 0" [10.1-BETA1 example]
Message-ID:  <2ED3DB50-B985-4382-8FF2-3B44E7E65453@dsl-only.net>
In-Reply-To: <1118046C-0FF7-49FC-82DA-DB9A7A310991@dsl-only.net>
References:  <1118046C-0FF7-49FC-82DA-DB9A7A310991@dsl-only.net>

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I've now spent time with rebooting and power-off/power-on for all 3 =
PowerMac G5's (one PowerMac7,2 and two PowerMac11,2's) and all 3 get the

> GDB: no debug ports present
> KDB: debugger backends: DDB
> KDB: current backend: DDB
> [ thread pid -1 tid 1006665719 ]
> Stopped at 0: illegal instruction 0
> db>

when they fail just before the Copyright notice would normally be =
displayed. None fail any earlier. At that spot none have failed any =
other way. It is the same SSD in all 3. (Happens with other SSD's as =
well.) Overall there is a mix of Radeon and NVIDIA display boards. =
Besides the SSD use and RAM upgrades the rest is stock equipment. scons =
used, not vt. (I've yet to try vt.)

Seeing a failure after the Copyright notice as been fairly rare in all =
my experiments from when I started last April or so. The ones that I've =
noted had Data Storage Interrupt reported. So far no examples of the =
above have been reported after the Copyright notice. So I'd guess that =
they are separate issues. Of course it seems that only in the last few =
days would I have seen the above sort of thing if it did happen after =
the Copyright notice: The prior history does not count for judgements =
about that.

=3D=3D=3D
Mark Millard
markmi at dsl-only.net

On Sep 16, 2014, at 8:15 AM, Mark Millard <markmi@dsl-only.net> wrote:

Using 10.1-BETA1 I added "options DDB" and "options GDB" to powerpc64's =
GENERIC64. (I also used WITH_DEBUG_FILES=3D, WITHOUT_CLANG=3D, and =
WITH_DEBUG=3D in /etc/make.conf.) So buildworld, kernel was basically =
just set up to have more of a debugging context around (including for =
any ports builds).

The result was new information about the PowerMac G5 boot hangups: The =
screen is no longer blank when the G5 is hung up without there being a =
Copyright notice yet. It says...

> GDB: no debug ports present
> KDB: debugger backends: DDB
> KDB: current backend: DDB
> [ thread pid -1 tid 1006665719 ]
> Stopped at 0: illegal instruction 0
> db>

(I had no ability to input at that point.) Normally the Copyright notice =
would have displayed instead of "[...]" and what follows. (I do not =
claim to have all the spacing, capitalization, and such correct above.)

That text is constant from hang to hang when it hangs just before it =
would normally output the Copyright notice: The numbers do not vary, =
much less the other text. It has never failed until after the two KDB =
messages are present. So far I've only tested one PowerMac G5, booting =
over and over for a few hours.



(I do not claim to be set up for remote kernel debugging. I just decided =
to let GDB go along for the ride when I added DDB.)

=3D=3D=3D
Mark Millard
markmi at dsl-only.net





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