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

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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