Re: Some tests with my Macintosh Centris 650
On 01/24/2015 12:01 AM, Finn Thain wrote:
> That's a very early crash. It could be caused by a NuBus slot interrupt
> being asserted, since these are non-maskable IRQs on some models. This can
> happen with SONIC ethernet, prior to the Linux macsonic driver being
> loaded.
>
> Try booting MacOS with no extensions loaded (hold down shift key when you
> hear the boot chime, and release it when you see the words "Extensions
> disabled").
Ok, I will give that a try next week. The Mac is located in my office
and I am not going to work over the weekend :).
I would actually buy a serial cable to help with the debugging. Is there
any particular cable that you can recommend?
> If this really is a regression, since 3.14, an obvious suspect would be my
> earlyprintk patch, commit 7913ad1ad834, which appeared in 3.16. But this
> crash looks to be too early.
I would be happy to try a kernel with that patch reverted if you want
to provide one.
>>> You might want to order a 16.666 MHz crystal as well, in case of
>>> instability at 40Mhz.
>>
>> Good idea!
>
> I've been there myself. I once clock chipped a PowerBook 520 CPU board. I
> desoldered the SMT 68LC040 CPU and replaced it with a 68040, and replaced
> the crystal at the same time. It worked, but the extra transistors and the
> extra frequency generated far too much heat for the passively cooled
> laptop to deal with. It needed a high-efficiency cooling system from a
> modern laptop, but there's no room for that.
Ouch :).
>>> The Quadra 650 (33 MHz) has a big heat sink on the CPU; I don't recall
>>> seeing one on the slower machines.
>>
>> The Centris 650 has a big heat sink as well which is why the guys from
>> the clockchipping website claimed overclocking them wouldn't be an issue
>> at all...
>
> Fair enough. I wonder if you need heat sinks on other chips -- who knows
> what clock lines could be affected by that crystal.
The website I linked earlier actually provides lots of statistics on the
topic [1]. Lots of users contributed reports at which clock rates their
Macs would still run stable.
Adrian
> [1] http://www.applefool.com/clockchipping/
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer - glaubitz@debian.org
`. `' Freie Universitaet Berlin - glaubitz@physik.fu-berlin.de
`- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913
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