User profile for user: amarjeetr
amarjeetr Author
User level: Level 1
36 points

Kernel panic Studio Display XDR + M2 Max MacBook Pro at 5K@120Hz (DCPEXT1 dual_pipe.c:180 sync_pipe_end_of_config)

I'm experiencing repeated kernel panics with my Studio Display XDR connected to a MacBook Pro M2 Max (Mac14,6) running macOS Tahoe 26.3.1 (25D2128). Three identical panics in three days.



CONFIGURATION:

  • MacBook Pro 16" M2 Max (Mac14,6)
  • macOS 26.3.1 (25D2128)
  • Studio Display XDR (serial: ***, firmware Version 26.3, Build 23D8128)
  • Connected via Thunderbolt/USB4 at 40 Gb/s (Bus 0, Receptacle 1)
  • Resolution: 5120x2880 @ 120Hz (ProMotion)
  • "Automatically Adjust Brightness" enabled
  • Use left rear port, might have tested with others too


This is a supported configuration — Apple's compatibility page confirms M2 Max supports Studio Display XDR at full 120Hz. The 60Hz limitation only applies to M1, M1 Pro, M1 Max, M1 Ultra, M2 (base), and M3 (base).


SYMPTOMS:

The Mac reboots unexpectedly with no warning. After restart, a kernel panic report is generated. The crash occurs every 1-2 days during normal use. It seems to correlate with display sleep/wake transitions but I haven't been able to pinpoint an exact trigger.


PANIC SIGNATURE (identical across all 3 crashes):

DCPEXT1 PANIC - apt firmware: dual_pipe.c:180 sync_pipe_end_of_config() -- - iomfb_mailbox(71)

DCP firmware: AppleDCP-1041.91.2~2-t602xdcp.RELEASE
RTKit build: root@Jan 17 2026@08:47:45~.release


The crash is in the Display Coprocessor (DCP) firmware running on the RTKit RTOS — specifically in the dual-pipe synchronisation code path. The 5K panel at 120Hz requires the DCP to split the display into two pipes, and the sync between them fails. The faulting task is always task 71 (iomfb_mailbox).

Kernel extensions in backtrace:

  • com.apple.driver.RTBuddy(1.0)
  • com.apple.driver.IOSlaveProcessor(1.0)


PANIC DATES:

  • 2026-03-15 07:42:58 UTC (incident: 5705E8C5-EF4A-4AC7-90A2-1C13E88FF5B2)
  • 2026-03-15 17:05:48 UTC (incident: 2D4FD13D-F65A-43C7-B8EB-2ECD168BEFCD)
  • 2026-03-17 19:57:58 UTC (incident: 2293C922-19D3-4464-96AD-1DACE7E21BE4)


WHAT I'VE RULED OUT:

  • Hardware defect: The crash is in DCP firmware, not hardware. The Thunderbolt link is solid at 40 Gb/s.
  • Cable issue: Connection is stable, no link errors.
  • GPU load: Crashes happen during normal use, not under heavy GPU load.
  • This would reproduce on any Apple Silicon Mac that supports this display at 120Hz, since all Macs running macOS 26.3.1 load the same DCP firmware (AppleDCP-1041.91.2~2).


WORKAROUND (which I will not be using):

Setting the refresh rate from "ProMotion" to "60 Hertz" might prevent the panic by avoiding the dual-pipe code path. However, I did not spend £3,000 on this display to run it at 60Hz. 120Hz ProMotion is a headline feature of the Studio Display XDR and a primary reason I purchased it. Running it at 60Hz makes it functionally equivalent to the original Studio Display at a fraction of the price.


I will be returning this display. It's not acceptable that a supported configuration on Apple's own hardware causes kernel panics every 1-2 days. If Apple resolves this with a firmware update, I'd consider repurchasing, but I can't keep a £3,000 monitor that crashes my Mac.


RELATED THREADS:

This appears to be the same underlying bug reported with third-party 4K@240Hz monitors:


The common pattern across all these reports: high refresh rates that push the DCP into dual-pipe mode trigger sync_pipe_end_of_config() failures. Multiple users report the bug was introduced with macOS Sequoia and did not occur on Sonoma.


I've filed a Feedback Assistant report with all 3 panic logs and a sysdiagnose. If you're experiencing the same crash, please file as well to help Apple prioritise a fix.


Is anyone else seeing this specifically with the Studio Display XDR at 120Hz?


[Edited by Moderator]


MacBook Pro 16″, macOS 26.3

Posted on Mar 17, 2026 3:35 PM

Reply
59 replies
User profile for user: Grant Bennet-Alder
Grant Bennet-Alder
User level: Level 10
143,495 points

Mar 17, 2026 4:34 PM in response to amarjeetr

Welcome to the Apple user-to-User Support Communities. Readers are other Users like you. Most Apple employees are prohibited from posting here, so they generally do not read here either.


That high-end display is said to not use Display Stream Compression. To run at resolutions higher that 5K at 80 Hz, and not using Thunderbolt-5, your Mac has to use Two display-generators to attempt to get enough bandwidth to support the extra data required. That is why you get the two half-displays with different stuff on them, and the kernel panics mention dual_pipe operation.


Two half-displays at 120 Hz does not fit on one Thunderbolt-3 or -4 cable at higher than about 73 Hz.


You could probably get to 120 Hz if you connected another Thunderbolt cable into the other ThunderBolt port on the display.

Reply
User profile for user: Servant of Cats
Servant of Cats
User level: Level 8
40,619 points

Mar 18, 2026 12:50 AM in response to amarjeetr

amarjeetr wrote:

I’m already getting 120Hz on my M2 Max MBP.


With the symptoms shown in your first post.


The question is, does the display run at 120 Hz without problems on the M4 Max MBP, which has Thunderbolt 5 ports?


How many cables are you using to connect the display to your M2 Max MBP, which has only Thunderbolt 4 ports? If the 120 Hz rate requires more bandwidth than a single Thunderbolt 4 connection can support, perhaps there's a not-well-documented requirement to connect it to the M2 Max MBP using two Thunderbolt cables – with the MBP and display somehow figuring out that there are two cables and that the load should be distributed among them.


You might want to call Apple Support and ask them if you should be connecting the M2 Max MBP to that display using two Thunderbolt cables. If they tell you that it is OK to do this, and encourage you to do it, and the issues stop, that would be strong evidence that a dual-cable setup is necessary with Thunderbolt-4-equipped Macs, if you want to be able to use the higher refresh rate.

Reply
User profile for user: Grant Bennet-Alder
Grant Bennet-Alder
User level: Level 10
143,495 points

Mar 18, 2026 12:33 PM in response to HDSche

HDSche wrote:

Adaptive Mode, TB5 cable on the TB5 port and on the TB3/4 port of the MBP, no other TB devices attached to the display.


To use any external device at Thunderbolt-5 speeds, the Mac's Port, the cable, and the device must ALL be ThunderBolt-5 rated.


When you connect an excellent Thunderbolt-5 cable and device to a Macbook Pro that is only capable of Thunderbolt-3 or -4 speeds, the highest possible speed is Thunderbolt-3/4 speeds of up to 40 G Bits/sec.


For this display withOUT Compression, on one cable, calculations suggest that will be limited to 5K at 80 Hz.


If you don't like your ThunderBolt-3 or -4 computer crashing, I recommend you set refresh rate to 80 Hz or lower.

Reply
User profile for user: Grant Bennet-Alder
Grant Bennet-Alder
User level: Level 10
143,495 points

Mar 20, 2026 12:26 PM in response to amarjeetr

Re: 80 Hz as a sweet spot for ThunderBolt -3/4 operation:


What I meant to say was that one 5120 by 2880 (5K) does not fit on a ThunderBolt-3/4 cable by itself, at any speed over about 80 Hz without the use of Display Stream Compression. That is using UHBR10, the highest that fits inside a Thunderbolt-3/4 envelope.


Suppose the display is divided into Left and Right half-displays, each 2560 by 2880, each on its own display-generator. Checking the Video Timings Calculator for using up to 50 percent or less of a UHBR10 channel: the highest rate that yields 50 percent utilization EACH is also about 80 Hz.


Two half-displays STILL does not fit on one Thunderbolt-3 or -4 cable at higher than about 80 Hz without using Display Stream compression.


You could possibly get to 120 Hz if you connected another Thunderbolt cable into the other ThunderBolt port on the Studio XDR Display. No one has reported success using two very short Thunderbolt cables that at this writing.


PUNCHLINE:

Need higher than 60 Hz, but ThunderBolt-3/4 Mac crashing with 'dual_pipe' in the panic report?

TRY 80 Hz rather than what the spec currently says, 120 Hz.



Reply
User profile for user: waylons2
waylons2
User level: Level 1
4 points

Mar 22, 2026 5:08 PM in response to amarjeetr

I've just had the same issue three times in a row. Bought this Studio Display XDR two days ago. Didn't have any issues up until this afternoon. I went to Youtube via Safari, looked for some 4K HDR content and after a minute of viewing it, I got the same screen that you show in your picture. My MacBook rebooted after a few seconds, and everything seemed fine. About 20 minutes later it happened again while I was reading an article in Safari. Two minutes after the second reboot the same thing happened while I had Safari open. I'm running an M2 Pro MacBook Pro w/12CPU & 19GPU cores.

I realize this is an older spec machine, but like you the Studio Display XDR is advertised as compatible with this spec. I did a shutdown, waited a bit and powered everything back up. Hoping that helps. I really don't want to have to return this beautiful display.

Reply
User profile for user: jamesgbeaumont
jamesgbeaumont
User level: Level 1
42 points

Apr 7, 2026 1:14 PM in response to amarjeetr

I have exactly this problem (including the image from OP) with Studio Display XDR and M4 Max Mac Studio with adaptive. I will switch to fixed 120hz and see if that helps, pending a fix from Apple. I have had the Studio Display XDR since launch day, so nearly 4 weeks, but today is the first time I have seen this issue and thus found this thread - but it has happened 3 times today.

Reply
User profile for user: jamesgbeaumont
jamesgbeaumont
User level: Level 1
42 points

Apr 7, 2026 8:49 PM in response to DonBenjamin

To add, I am running the latest Studio Display XDR firmware (Version 26.4 Build 23E246)and macOS 26.4. That said, I can't find any kernel panic reports (checked /Library/Logs/DiagnosticReports and ~/Library/Logs/DiagnosticReports) but I did get the strange right-hand half of monitor image per OP for a few seconds followed by reboot. I have reported the symptoms to Apple and shared this thread.

Reply
User profile for user: Grant Bennet-Alder
Grant Bennet-Alder
User level: Level 10
143,495 points

Apr 21, 2026 12:10 PM in response to jamesgbeaumont

Your post-failure photograph is typical of a failure when using TWO display-generators, one for Left half-display and the other for Right half-display.


Your M4 Mac Studio MAX has Thunderbolt-5 ports. Are you using a Thunderbolt-5 cable such as the one that shipped with the display?


I expect that if set up 'correctly' using Thunderbolt-5 Port and cable the new 5K display XDR should run on ONE display-generator over ThunderBolt-5, using DisplayPort UHBR20 speeds of 77.37 G bits/sec, no Display Stream Compression required.


That it does something different is the essence of these complaints.



Reply

Kernel panic Studio Display XDR + M2 Max MacBook Pro at 5K@120Hz (DCPEXT1 dual_pipe.c:180 sync_pipe_end_of_config)

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.
Learn more Sign up