GPU Not Found - Kernal Panic on 2019 Mac Pro

Thanks for your help.

Here goes EtreCheck report, but it shows no major issues.

Yes, I migrated from iMac Pro. I had my first Mac Pro returned and in the process I installed Catalina on iMac Pro from scratch, so I doubt it left any problematic remnants: the same monitors, and peripherals.

A few pointers:

1. The panic occurs ONLY in deep sleep mode. A couple of hours of sleep doesn't matter.
2. After reboot, no issues whatsoever.
3. From time to time, USB devices connected to a USB C hub which is connected, in turn, to a thunderbolt port, are not detected(powered okay, but not recognized by the system). This USB C hub (satechi) doesn't work if connected to a USB 3.0 port. But it behaved the same with the previous Mac Pro.

I'm pulling my hairs out now.

Okay, I reinstalled Catalina(not a clean installation from scratch, just a simple reinstallation from internet by pressing SHIFT+OPT+CMD+R), put my Mac Pro to sleep for more than 3 hours.

It woke up just fine.

Not sure it solved anything, but GPU kernel panics are gone for now.

But I'm not putting this machine to sleep anyway. I'll just give it a nice cold shutdown from now on.

Deep sleep leads to the same kernel panic.

If I don't put it into deep sleep, it runs just fine.

I have to decide whether to return this machine again soon. Only one week left out of the 14 days. Bummer.

Just to be sure...

I have three external Promise enclosures and one internal one (Pegasus R4i) installed.

BUT the 'GPU is not Found' kernel panic had occurred the first time I put the machine to sleep even before I installed Promise stuff.

A second look at the kernel panic report revealed that the panic had already occurred well before I waked it up: timestamp shows probably the kernel died when the machine tried to go into deep sleep after the default 3 hours of sleep.

My Mac Pro needs at least 3 hours of sleep (it needs to go into deep sleep) before I can check if any suggestions worked or not. Arrggh.....

I'll give it a try anyway. Thank you.

Just a thought while waiting for my Mac Pro go into deep sleep.

I've experienced tons of kernel panics on 2017 iMac Pro until Catalina came on. All related to T2 chip: the infamous t2 chip kernel panics were all over me.

And from experience I got pretty sure that t2 chip (bridge os) kernel panics occur on my iMac Pro due to overloaded IO(thunderbolt bandwidths): 9 out of 10, iMac Pro panicked when editing tons of clips in Final Cut Pro X or after copying a lot of huge ProRes clips via thunderbolt ports.

Even the dreaded GPU reset/restart kernel panics were not rare. Even now iMac Pro sitting on another desk dethroned by the new Mac Pro shows a couple of GPU restart crash reports. Apparently it restarted a couple of times while in deep sleep.

So I suspect the New Mac Pro's T2 chip might be as imperfect as the other Macs succumbing to this particular kind of kernel panics.

Which means... I'll have to grin and bear it until Apple finds a silver bullet. Darn it.

Just a thought.

p.s. How can I correct that typo 'Kernal' in the title?

Update.

I was wrong in stating that only deep sleep leads to this kernel panic.

An hour and a half of sleep later my Mac Pro panicked again: GPU is not Found.

The only workaround, at least for now, is never put it to sleep.

Unfortunately, the problem came back.

My Mac Pro now even fails to detect displays (two) at all or only detects only one of them when it boots up after a certain amount of time, like, about 3 to 4 hours(just about the same amount of time required for the standby mode to kick in.)

Force restarts by pressing the power button might or might not work. An SMC reset always work.

Just my guess, but it seems as if the Mac Pro fails to provide enough power to one of the AMD Pro Radeon II Duo GPU units when they get cold (in deep sleep or powered off state) after an ample amount of time.

The problem never occurs between short power cycles or in sleep mode (not standby - deep sleep).

Argh... 14 days have passed since the purchase, so I can't return it now.

An SMC reset is becoming a daily hassle.

The only surefire solution as of now is leave the machine running 24/7.

Would plugging it directly into the wall outlet instead of using a power strip make any difference?

Or should I suspect a defective PSU?

Can a defective PSU have the machine run for days? My Mac Pro shows no problem at all after a successful restart.

Like I mentioned, the machine runs just fine after a successful (re)start. Could a defective CPU do that?

It seems I may be the only 28-core Mac Pro user having these issues...

Thanks anyway for your continued help.

Haha 😅

Sorry, I must have been nagging you too long.

I just can't imagine a defective PSU letting the machine run for days without a hitch after a successful startup.

I'm pulling my hairs and bashing my head :-(

Oh, one more thing.

I'm waiting for my dual XDR monitors to arrive (back-ordered). In the meantime, I'm using two dell monitors: HDMI(32inch) and displayport (via a CalDigit dock). It's always the 32 inch monitor that fails to be detected: I tried the Caldigit displayport but shows the same symptoms. Even when waking up from deep sleep, the 27inch one always seems to light up a bit before the kernel panics occurs.

Anyway, I might have a better luck with native apple XDR monitors.

I'll report what happens when I have them.

But what about the symptom of Vega II Duo MPX module losing one of its GPU unit when the 32incher fails to be detected?

When it happens, System Info shows only one GPU (Vega II 32GB) not Duo, and Activity Monitor loses it GPU tab.

I'll disconnect the 27"er and see what happens. Thanks.

Think I found the culprit.

I turned off 32" Dell monitor's sleep mode (monitor sleep) and the kernel panic is gone. 27incher has no sleep mode, probably that's why it always lights up when I try to wake the machine up.

Sleep mode works fine now. No more panics.

Thanks for all your help, much appreciated.