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Old 07-20-2019, 09:00 AM   #1
martinlangley
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OSX - Mac Pro thermal problem


Hi all

This is a problem which appears to have stumped all the Mac boys so thought I'd try my luck here. - No surprises since they're all old women and you have to come here to find the real men!

I have a 2010 - ish Mac Pro 5,1. Its running either Snow Leopard for legacy compatibility or Mojave when I'm in a flashy mood.



I have a single processor tray which works fine for practical purposes but I also have a dual processor tray which is where the challenge arises. In order to get the dual processor tray to work, I have to put it in the freezer for half an hour before fitting it to

the machine. If I do this it boots fine and runs for a good five minutes before the second processor (B) warms up, I get a red light on the tray and the machine shuts down.



If I try and start it without putting the tray in the freezer it fails to boot and the red light comes on. All the usual suspects have been tried, replacing thermal paste on heatsinks, replacing spring rivets on Southbridge chip heatsink etc etc. When the B processor is removed, the machine boots fine and the fans are noisy but can be slowed with software.



After much investigation it seems there is a fault/misalignment in the temperature value/voltage being reported by the hardware to the SMC device, which is (mis)detecting an overtemp and shutting the system down when it needn't.



The question for you guys is this. The SMC firmware is updated regularly and is accessible with software debugging tools (MacProSMCUpdate11.dmg). Can some clever person more up to speed (than me) with Mac firmware and software generally, point me in the right direction as to how I can:

a) locate the B processor temperature detection logic.

b) modify it so it either ignores the erroneous overtemp data or re-interprets it to give a correct (ish) value which does not cause a red light and a shut down.

c) install the tweaked software so as to avoid/evade the shut down issue?



That should keep you guys out of trouble for a few minutes at least, and stop you hanging round street corners and chewing gum.



Best



Martin
 
Old 07-20-2019, 09:43 AM   #2
TB0ne
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Quote:
Originally Posted by martinlangley View Post
Hi all
This is a problem which appears to have stumped all the Mac boys so thought I'd try my luck here. - No surprises since they're all old women and you have to come here to find the real men!
There are many 'old women' on here who are far more skilled.
Quote:
I have a 2010 - ish Mac Pro 5,1. Its running either Snow Leopard for legacy compatibility or Mojave when I'm in a flashy mood.

I have a single processor tray which works fine for practical purposes but I also have a dual processor tray which is where the challenge arises. In order to get the dual processor tray to work, I have to put it in the freezer for half an hour before fitting it to the machine. If I do this it boots fine and runs for a good five minutes before the second processor (B) warms up, I get a red light on the tray and the machine shuts down.

If I try and start it without putting the tray in the freezer it fails to boot and the red light comes on. All the usual suspects have been tried, replacing thermal paste on heatsinks, replacing spring rivets on Southbridge chip heatsink etc etc. When the B processor is removed, the machine boots fine and the fans are noisy but can be slowed with software.

After much investigation it seems there is a fault/misalignment in the temperature value/voltage being reported by the hardware to the SMC device, which is (mis)detecting an overtemp and shutting the system down when it needn't.

The question for you guys is this. The SMC firmware is updated regularly and is accessible with software debugging tools (MacProSMCUpdate11.dmg). Can some clever person more up to speed (than me) with Mac firmware and software generally, point me in the right direction as to how I can:

a) locate the B processor temperature detection logic.
b) modify it so it either ignores the erroneous overtemp data or re-interprets it to give a correct (ish) value which does not cause a red light and a shut down.
c) install the tweaked software so as to avoid/evade the shut down issue?

That should keep you guys out of trouble for a few minutes at least, and stop you hanging round street corners and chewing gum.
This isn't anything to do with an operating system, and while the Mac OS is based on a unix based system, it is NOT. What you're asking us to do is reverse engineer the firmware on a piece of Apple hardware, tell you where the problem might be, and then tell you how to install this patch.

Whether it's right or not, the Apple EULA and terms prohibit doing this, period. If you want a solution to your Apple hardware problems, Apple is the gateway to that. This also appears to be the same machine you asked about here:
https://www.linuxquestions.org/quest...on-4175650184/

...where you were told it only accepts certain processors. Have you heeded that advice, or did you put something else in? You have old hardware, and old APPLE hardware to boot. Apple isn't known for making the most high-quality, user-serviceable devices out there. I do run Linux on an iMac, so a good number of limitations have fallen away from that hardware, but there comes a point where the Apple firmware comes in to play...and that is a black box. Unless you can get Apple to answer your question, you're done.
 
Old 07-20-2019, 02:13 PM   #3
martinlangley
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The previous post was also me but the problem was different. It was traced eventually to a defective motherboard which has now been disposed of. This is a new problem on a new machine.

There are multitudinous persons running Mac OS X on PC hardware as Hackintoshes in blatant violation of Apple's "EULA" all day every day and I see no attempt to do anything about this. The issue has arisen because Apple keep the hardware details of their machines so tightly under wraps (in violation of competition law!) that they become near impossible for a user to fix. A lawyer would most likely argue that in these circumstances the EULA becomes unenforceable.

All I'm asking for is some help in circumnavigating this iniquitous conduct from people who are likely to have the means to do it. If you're not one of them, fine, but that doesn't mean there are no others of a more helpful disposition. In fact my various postings have resulted in significant progress in a short time. I remain optimistic.
 
Old 07-21-2019, 09:49 AM   #4
TB0ne
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Quote:
Originally Posted by martinlangley View Post
The previous post was also me but the problem was different. It was traced eventually to a defective motherboard which has now been disposed of. This is a new problem on a new machine.
And the question still stands on whether or not you're using the recommended Apple hardware in the add-on board.
Quote:
There are multitudinous persons running Mac OS X on PC hardware as Hackintoshes in blatant violation of Apple's "EULA" all day every day and I see no attempt to do anything about this. The issue has arisen because Apple keep the hardware details of their machines so tightly under wraps (in violation of competition law!) that they become near impossible for a user to fix. A lawyer would most likely argue that in these circumstances the EULA becomes unenforceable.
There is no 'competition law' that applies here. They don't have a monopoly, and have every right to do whatever they want with their designs. And while they WANT to prohibit third parties from repairing their devices, they legally cannot. What they CAN do is make it difficult, and they do.
Quote:
All I'm asking for is some help in circumnavigating this iniquitous conduct from people who are likely to have the means to do it. If you're not one of them, fine, but that doesn't mean there are no others of a more helpful disposition. In fact my various postings have resulted in significant progress in a short time. I remain optimistic.
Good for you. And your question essentially boiled down to "I have a broken Apple product, and they won't fix it. I want someone else to reverse-engineer things for me, and then tell me what to do".

If this is a project of interest to you, then you should do it and enjoy the learning process. Otherwise, there are MANY third-party Apple repair shops that can probably do it for you. But asking us to (essentially) do a ton of research, coding, etc., to work on YOUR problem for free isn't a good thing, regardless of a 'helpful disposition'. And you still don't address the fact that the hardware itself could be broken/flaky, and that you DO have a genuine issue. Or would you like us to also do hardware diagnostics for you?

Again, as said previously, if you were running Linux, there may be things you can do. The iMac I run openSuSE Tumbleweed on uses more memory than Apple supports, better wifi hardware, and the second SATA port magically works. On OSX, the system wouldn't even boot. But you are locked into the Apple ecosystem, so your choices are:
  • Get Apple to repair the device
  • Take it to a third party
Those third-party shops have spent YEARS reverse engineering Apple's products, so they can repair them.
 
Old 07-22-2019, 09:24 AM   #5
snowpine
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Last edited by snowpine; 07-23-2019 at 05:50 PM.
 
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