Kernel Panic With 4k 240 Hz External Monitor

When connected to my Alienware AW3225QF 4k 240 Hz monitor with my M2 Max MacBook Pro, I encounter a kernel panic and a system crash at least once every 2 days. Is this issue specific to the high resolution and refresh rate combo?


panic(cpu 0 caller 0xfffffe001836b410): DCPEXT2 PANIC - apt firmware: dual\_pipe.c:180 sync\_pipe\_end\_of\_config() -- - iomfb\_mailbox(68) apt firmware: dual\_pipe.c:180 sync\_pipe\_end\_of\_config() -- RTKit: RTKit-2758.1.1.release - Client: AppleDCP-811.1.1\~754-t602xdcp.RELEASE !UUID: a1000010-2140-1ed5-a178-80d201401ed5 ASLR slide: 0x000000000021d000 Time: 0x000000090ceeff39



MacBook Pro 16″, macOS 15.0

Posted on Oct 18, 2024 4:37 AM

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Posted on Mar 20, 2025 6:51 AM

OK, I got some 'good news' here. Been talking to the Apple Support, explaining the situation and just aknowledging.

The person found a 'tracker' about this issue, as of yesterday. Apple team is currently working on this to fix it in an upcoming firmware update. He also said that in the tracker it says that reducing the framerate to 120Hz in the meantime is a workaround in the meantime.

76 replies

Jan 28, 2025 6:41 AM in response to Infilak

Debugging and Reporting steps:

Make certain you have applied all available software updates, because no one is willing to debug a problem that might have been seen and solved already.


Then you need to go through the 'regular" steps to eliminate added software as the cause of the problem:


• Run In Safe Mode, where no third-party add-ons are loaded

• create a new "clean" User account, and run with that to eliminate contamination in your regular User account

• run the diagnostic to check for GROSS issues. "no fault found" is not the same as "all is well".


[You already did this step.]

If you are seeing kernel panics, post a panic report. Some panic-reasons suggest a Hardware issue. There is a procedure that can allow you to find those reports to post one. Ask for assistance if you need it.


if you take it to an Apple service provider first, they CAN run their diagnostics, which are a bit more comprehensive that the User diagnostics. In the very small amount of time they are run, “No faults detected” still does not mean “All is Well” but at least there are no detected GROSS problems. Unless they can find a fault, they will return your computer unchanged.


Genius Bar technicians are NOT trained to read panic reports and computer logs. When you present your computer at the Genius Bar with the expectation of a quote to repair it, you must generally meet these criteria:


• your Mac won't do anything

• your Mac fails diagnostics

• your Mac has a problem you can repeatably demonstrate on demand

one other oddball case:

• Apple online support has DIRECTED a Service Provider to replace specific components inside your Mac, such as the mainboard or display. Bring proof, such as case number.


The telephone support people are more likely to work with you. They will insist that you go through the motions to eliminate software issues. But when they get to the end of their list, you should insist on having your problem escalated to a specialist. Specialists are more likely to actually read your panic reports, and to agree this is a problem and DIRECT an Apple service provider to swap things (likely mainboard) for a new one.


You MUST have a Trusted backup before submitting your Mac for service. if the mainboard is swapped out, the boot drive will be swapped out as well, and you will not get your files back.

Jan 28, 2025 7:53 AM in response to Infilak

I have a ROG PG32UCDM with firmware MCM108 and a Mac mini m4 pro. I connected the monitor with a high quality Thunderbolt 4 usb-c cable so I am certain it is not the cable's problem. This issue still exist on macOS 15.3. As long as I set the monitor refresh rate to 240Hz or 48-240Hz, a kernel panic will occur once a while, especially when mac mini was under heavy load such as running video games. this never happened when I set the monitor refresh rate to 120Hz.

Jan 28, 2025 5:16 PM in response to null1337

<< I’m really hoping Apple is aware of it ...and will release a fix soon. >>


the thing is, when you post on this User-to-User forum, if other readers can not think of a fix, that's the end of the line. Apple does not troll these forums looking for problems. they need well documented BUG reports that have all the information needed to re-create the problem in their labs. and the more of them they have, the more urgent the problem seems.


<< ... and will release a fix soon. >>


no fix will be forthcoming unless/until YOU and everyone else here reports it as a problem.

you can call Apple telephone support OR

you can use the feedback links and choose BUG REPORT:


Product Feedback - Apple



.

Dec 15, 2024 9:30 PM in response to Infilak

I am quite optimistic that this issue can be solved via software update. Just hope they prioritize it somewhat higher. 240Hz displays are not widespread yet and Apple does not sell a display with a refresh rate greater than 60Hz themselves. :(


Reason why .. because for me (M2 Studio) it runs for hours and days without issues doing all kinds of different tasks. Just occasionally (every 2-3 days, after 20+ hours of use) there is one reboot. Does not point usually to a hardware issue ..


Jan 21, 2025 8:23 AM in response to Infilak

Apple only fixes things that are broken, and broken is often defined as something outside of specifications. For the original Author's Mac:


MacBook Pro (16-inch, 2023) - Technical Specifications - Apple Support


M2 Max

Simultaneously supports full native resolution on the built-in display at 1 billion colors and:

  • Up to four external displays: Up to three external displays with 6K resolution at 60Hz over Thunderbolt and one external display with up to 4K resolution at 144Hz over HDMI
  • Up to three external displays: Up to two external displays with 6K resolution at 60Hz over Thunderbolt and one external display with up to 8K resolution at 60Hz or one external display with 4K resolution at 240Hz over HDMI

Thunderbolt 4 digital video output

  • Support for native DisplayPort output over USB‑C

HDMI digital video output

  • Support for one display with up to 8K resolution at 60Hz or 4K resolution at 240Hz


--------

As I read those specs:

higher than 60 Hz refresh rates are ONLY supported on the built-in HDMI port with an ULTRA HDMI 2.1 spec HDMI cable, NO ADAPTERS.


All others appear to be limited to 60 Hz refresh rates, max.

However, kernel panics are NEVER an intended outcome, so 'that it panics' is still a Bug.

Jul 10, 2025 4:27 AM in response to wayanbarre

hi, any update here?


I'm getting the same issue and it's pretty critical as the job is lost few times already because us such a HARD restart...


panic(cpu 6 caller 0xfffffe00129b6138): "mismatched swapID's 234895 vs 234897\n" @UnifiedPipeline.cpp:14558
Debugger message: panic
Memory ID: 0x6
OS release type: User
OS version: 24F74
Kernel version: Darwin Kernel Version 24.5.0: Tue Apr 22 19:54:29 PDT 2025; root:xnu-11417.121.6~2/RELEASE_ARM64_T6030

Jul 18, 2025 3:55 AM in response to RsProd

Has anyone tried the macOS Tahoe beta? That's my only remaining hope...


According to the status of my bug report, Apple cannot reproduce the issue... which is most likely because they simply don't have a 240Hz OLED monitor. Otherwise, it should be trivial to reproduce. They probably don't consider this issue important enough to buy such a monitor for debugging purposes...

Kernel Panic With 4k 240 Hz External Monitor

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