iMac Pro Kernel Panic iMac Pro using 2nd Display

Discussion in 'iMac' started by anaudiopro, Apr 23, 2018.

  1. anaudiopro macrumors 65816

    anaudiopro

    Joined:
    Mar 7, 2017
    #1
    Anyone else ever experience a kernel panic and total crash of their iMac Pro while having a 2nd monitor connected? It's connected to a very good 2K BENQ display via USB-C to DisplayPort. About one minute after connecting it for the very first time, BOOM! Crash... Then the machine rebooted itself, and (fingers crossed) seems to be working fine now.
     
  2. mcc9999 macrumors newbie

    Joined:
    Jun 3, 2018
    #2
    I have been having the same problem everyone else is writing about in Apple Support communities and all over the internet. I have sent 4 files x2 separate times to Apple engineering (4 gigs each time) and they have finally determine it is the embedded Raideon Pro Vega 64 video card which part of the motherboard (not plug in video card). I have new motherboard on order that is going to be replaced. I have also read about folks getting their iMac Pro replaced and the same problem happening with clean "Macs" with no additional software or peripherals (I am assuming Apple did not know with these folks that the GPU was the issue). My take is that Apple has found the problem and they probably had to get AMD to fix the GPU in their video card, so now the new motherboard and hopefully new AMD Raideon Pro Vega 64 card are fixed. I will let you know. If you are not sending large files to Apple to review (what I did) you may be wasting a lot time with all these theories out there. My reason for posting is, if everyone does what I did (send crash files to Apple), we may all get to the bottom of this quicker. I not certain this is the fix until I get the new motherboard with new embedded video card and the problem (kernel crashes) goes away. My kernel crashes happen now nonstop. that is another question, why did the frequency increase so much if it was always a hardware issue.
     
  3. ThatSandWyrm macrumors regular

    ThatSandWyrm

    Joined:
    Oct 30, 2017
    Location:
    Indianapolis
    #3
    Haven't had THAT kind of crash for a while now. I have two Dell 5K displays attached to my iMP, and one of them does double-duty as a 4K display for my Windows box. So I'm always switching the inputs on it.

    What DOES crash my machine since the 10.13.4 update is my external GPU box. It's the same Sonnet enclosure that Apple was selling to developers a year ago, and it's got a fully supported RX580 in it. But if I leave it plugged in, the machine crashes on wake-up.
     
  4. anaudiopro thread starter macrumors 65816

    anaudiopro

    Joined:
    Mar 7, 2017
    #4
    Should I be looking into this further then and calling Apple to see if there is some known issue with the GPU and if my machine needs to be replaced? What you are describing would bring on like a mass recall sort of thing.
     
  5. campyguy macrumors 68040

    Joined:
    Mar 21, 2014
    Location:
    Portland / Seattle
    #5
    Yes on 3 of my 5 base iMPs in my office and home office, and with a 4k BenQ display FWIW. Figured it out an "fixed" it PDQ, relied on past experience with DP cables. No issues with the other two iMPs. I learned my lesson in the difference between VESA "certified"/"compliant" and "compatible" cables, buying only sources with certified cables. The three that had issues were set up by one of my employees as I was out of two, he purchased some off-brand that listed that they are compatible with DP 1.2. I set up the other two, one in a field office and the other in my home office, and I stuck with one of my go-to suppliers (Accell, which was the only one of 3 suppliers that had a suitable product available - a 6 ft cable that's compliant with VESA DP Alt mode on USB-C ver. 1.0; I didn't see a like cable from either Belkin or StarTech, IDK if these companies have a like cable yet). Apple sells a 5 ft cable by Moshi that's compliant up to 5k @ $50.

    I bought 3 more of the Accell cables for the 3 iMPs that had KPs when I returned and swapped them out when the arrived. Zero issues with all 5 iMPs with the Accell cables - connected to either a BenQ, an LG, or an Eizo display, all 4k UHD. My 2¢.
     
  6. anaudiopro thread starter macrumors 65816

    anaudiopro

    Joined:
    Mar 7, 2017
    #6
    Can you provide a few links to cables you'd recommend on like Amazon? I am also using a BENQ display. It is 2560x1440

    Thanks!
     
  7. campyguy macrumors 68040

    Joined:
    Mar 21, 2014
    Location:
    Portland / Seattle
    #7
    I embedded a link to the Accell cable in my OP, here it is again! :D Accell provides direct links to resellers on their product page, Amazon is one of them, I think Staples and Newegg are the other two for this cable. Amazon is the reseller I used, got it delivered the next day on both orders.
    https://www.accellww.com/collections/cables/products/usb-c-to-displayport-cable

    I have my iMP connected to an LG 32UD59 (32", UHD, DP plus 2 HDMI 2.0) via the Accell cable. At my office, another iMP is connected to a BenQ BL2711U. Both work flawlessly.

    I've only seen the Moshi on Apple's site and their own product portal. FWIW, I try to keep up with product availability and still have not seen any other like cables from makers I trust, needing to keep my 50-odd employees working and not whining let alone sticking with certified products in their workflows. I did check out the sites of Eizo (a bit of a PITA to find anyway), StarTech, and Belkin after my post and came up empty. What I am seeing more of are TB3 adapters that terminate in dual DP 1.2 ports that offer compliance with DP 1.2 (a good thing), however, the adapters cost $75 and up and then you'd still need compliant cables (available on the DisplayPort.org product portal) - I have a few vendors, they're indicating that most of the manufacturers they work with are going the adapter route for cables that terminate in DP connectors as a bunch of new displays coming out will have the USB-C interface - VESA has just certified a bunch of 8k cables/adapters for computers and almost all have the USB-C interface on both ends. Right now, I think that the Accell cable and Moshi cable are the only two available cables in this vein that are compliant and have a DP interface on the terminating end of the cable.
     
  8. anaudiopro thread starter macrumors 65816

    anaudiopro

    Joined:
    Mar 7, 2017
    #8
    Thank you!
     
  9. concluded macrumors newbie

    Joined:
    Jun 30, 2018
    #9
    My iMac Pro kernel panics regularly, and in increasing frequency when I have two external monitors connected (seemingly mostly related to the one connected via USB-C to DP). I'm currently on the third USB-C to DP adapter I've tried and I'm still getting kernel panics and spontaneous reboots. I tried the Moshi cable purchased directly from Apple, a Plugable cable, and now a Cable Matters.
     
  10. campyguy macrumors 68040

    Joined:
    Mar 21, 2014
    Location:
    Portland / Seattle
    #10
    Welcome to these Forums. Now, a bit of questioning and prognostication.

    Which display model(s)? Are they new, or from a previous setup? You've offered that you have multiple displays but list a singular cable as opposed to using two of the same cables. You've listed the multiple displays but not offered that you are using them simultaneously, and at which resolution(s) - I frequently have one in portrait mode and a second in landscape mode while attached to my iMP. You wrote "monitors" as opposed to "displays" - to me, monitors have speakers and displays do not have speakers. If you respond, don't jump in until you read the rest of this...

    A nit to pick, from personal experience - the cables. First, the Moshi cable does not list the iMP as a compatible model; yes, the Apple product page lists the iMP but Moshi's product page does not. Second, none of the three brands you've listed made a certified DP cable (I do check the DP.org product portal for manufacturers that take the time to get their products certified); I'm aware of the text claiming that Moshi's cable was certified by VESA for 5k, but that's their claim and it's still not on the DP.org product portal - I've purchased and tested/tried Cable Matters mDP>DP cables and the 4 that I tested returned power over Pin 20, therefore not being compliant with VESA standards.

    Regarding your displays, if they're from a previous setup, reset them. Read up on DisplayID. Information is embedded in the monitor/display as well as your Mac's NVRAM, and a compliant cable conveys that information between Mac and display. And, reset your iMP's NVRAM - before you reset the NVRAM get a data dump from Console.app, for reference as the recent kernel panic information is stored in NVRAM and resetting the NVRAM will wipe that data. And...

    Buy that cable that I linked to above. Accell has long provided VESA and USB-IF certified products, and they work properly - and I trust them, although I do check them with my multimeter first before connecting them to my Macs or PCs. There are two connected to my iMP right now, to a 32" LG and a 27" BenQ, both 4k UHD displays via a pair of that cable. The LG was new, zero issues. Knowing that I was moving from an rMPB to the iMP, I reset the two BenQ displays before moving one to each of my two workspaces (the second BenQ is attached to my Mini Server).

    Last, using my LG as an example, the workspace controlling utility has been updated at least 4 times in the past few months and is finally not causing stability problems. Check to see if a utility running in the background could be the culprit. Finally, you also didn't offer whether your displays have a USB hub and if it is or isn't connected - I don't connect to my display's hubs and can't comment on this bit.
     
  11. concluded macrumors newbie

    Joined:
    Jun 30, 2018
    #11
    Thanks for the response!

    Both of the external monitors (if speakers are the distinguishing feature of a monitor vs a display, they would both be monitors) were in use for a long time with previous computers (more than a year and a half with a 5K iMac, connected to other computers before that). One is a Dell U3011, usually connected via DP, and the other is an Asus VW266H connected by HDMI (no DP on that monitor). Both are connected simultaneously - though to experiment I had run the iMac Pro with no external monitors connected at all and it ran for a week or so with minimal problems, then with only the Asus connected by HDMI, which also seemed to last a while. That's why I've zeroed in on the USB-C to DP as a primary culprit.

    I have tried connecting the Dell via HDMI as well, and the computer stayed up and running for something like 5 days that way, but the monitor can't be run at native resolution (using Apple's USB-C to HDMI adapter, anyway).

    I did purchase the Moshi cable thinking that it's the one Apple recommends (as you say, Apple says it's compatible with the iMac Pro on their site). With the old 5K iMac (late-2015 model), I had connected both displays to the Thunderbolt ports (mini-DP to DP and mini-DP to HDMI) and never had a problem. Obviously the iMac Pro doesn't have the miniDP-style Thunderbolt 2 ports anymore.

    But what makes me suspicious that it might not be just the external display(s) is that I had a crash almost immediately after plugging in a Firewire adapter (using USB-C to Thunderbolt 2, Thunderbolt 2 to Firewire 800), I've had many crashes while working in Photos specifically, and when I was first setting up the computer I was trying to use a Thunderbolt 3 to Thunderbolt 2 adapter and a Thunderbolt 2 cable to connect to the old iMac to transfer files and it had a mysterious failure halfway through. I ended up setting it up from scratch instead.

    I haven't tried doing anything to the displays themselves. I'll try that.

    I have gone ahead and ordered that Accell cable to try that next.

    The Dell monitor does have a USB hub but I've never actually plugged it in. The only connection to either one is the display cable.
     
  12. campyguy macrumors 68040

    Joined:
    Mar 21, 2014
    Location:
    Portland / Seattle
    #12
    It's easier for me to reply in this fashion, I'm a quick read.

    Cutting to it, I'm going to agree that the chain of adapters you've terminated in FW is most likely the source of your issues here - that TB adapter is meant to connect solely to other TB devices. Respectfully, you've attempted to fashion an adapter that shouldn't even exist. Only one TB3 dock exists with FW (FW800 only), made by OWC. Firewire is not a subset of TB 1/2/3 - the OWC dock has a chipset that addresses the relevant data "conversion", and at $350 it's not cheap. I wouldn't be a bit surprised that some damage may have been done to your iMP, I'd ditch your "adapter" PDQ and not use it.

    You didn't offer which type of devices you're wanting to connect using FW. FWIW, the only remaining device in my company using FW is an old G-Tech G-RAID but it's also got an eSATA interface and I connect to it via a $15 USB-A to eSATA converter. I'm going all in with the USB-C interface from hereon until the next port style takes over, but by then I'll be on a beach in the South Pacific...

    Back on point here, seriously, ditch the FW daisy chain. If it's a camera or other specific non-storage device, get the OWC dock; if it's a storage device you're wanting to connect to, extract the drive(s) and put them in a USB enclosure or use a bare drive adapter. Do buy the Accell cable, for the reasons I offered in my OP. Regarding your Dell's USB hub, I suggest disabling in the display's OSM - I've opened up a few of our Dells and I found zero indication of shielding while the BenQ displays do have USB hub shielding (many of Dell's displays guts are made by BenQ's AOC subsidiary, including the panels).

    Keep us posted. Cheers.
     
  13. concluded macrumors newbie

    Joined:
    Jun 30, 2018
    #13
    The Firewire adapter was to connect an old DV camcorder, but I don’t think it’s terribly important except as an additional data point. Only time I had tried connecting it was about a week ago, and after the kernel panic I disconnected it and it hasn’t been reconnected. This was long after the other problems had started.
     
  14. odinbar macrumors newbie

    Joined:
    Jul 20, 2018
    #14
    do you changed cables, the problem was solved?
    I also have 2 monitors connected to iMac pro ,
    and I have a problem with the fact that the computer freezes to death, when I watch youtube in the browser safari, the mouse cursor continues to move, but everything else freez, and helps only hard reset.
    you had such a thing?
    I have the latest update 10.13.6
     

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