Kubuntu 25.04: Blank Screen After Sleep with Apple Studio Display (Thunderbolt)

Support and Help
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1

Ubuntu Version:
Kubuntu 25.04 (happened on 24.04 as well)

Desktop Environment:
KDE Plasma

Problem Description:
Hi all,

I’m running a fresh Kubuntu 25.04 install and encountering an issue where my Apple Studio Display (connected via Thunderbolt) remains blank after waking from sleep. The system seems unresponsive, as Ctrl+Alt+F2 doesn’t bring up a terminal, and I need to hard reboot. Everything works fine before sleep.

Relevant System Information:
System Details:

  • OS: Kubuntu 25.04
  • Kernel: 6.14.0-15-generic
  • CPU: AMD Ryzen 9 9950X3D
  • GPU: AMD RX 9070 XT (discrete) + Integrated Radeon Graphics
  • Display: Apple Studio Display (connected via Thunderbolt 3 to motherboard)
  • Session: Wayland
  • Drivers: Latest amdgpu drivers installed

Raw journalct logs

desktop kernel: nvme nvme0: 16/0/0 default/read/poll queues
desktop kernel: xhci_hcd 0000:4b:00.0: xHCI host controller not responding, assume dead
desktop kernel: xhci_hcd 0000:4b:00.0: HC died; cleaning up
desktop kernel: usb usb5-port1: couldn't allocate usb_device
desktop kernel:  nvme0n1: p1 p2
desktop kernel: hub 6-0:1.0: activate --> -19
desktop kernel: usb 1-3: new full-speed USB device number 2 using xhci_hcd
desktop kernel: usb 3-7: new full-speed USB device number 2 using xhci_hcd
desktop kernel: ata7: SATA link down (SStatus 0 SControl 300)
desktop kernel: ata1: SATA link down (SStatus 0 SControl 330)
desktop kernel: usb 1-3: New USB device found, idVendor=046d, idProduct=c52b, bcdDevice=12.09
desktop kernel: usb 1-3: New USB device strings: Mfr=1, Product=2, SerialNumber=0
desktop kernel: usb 1-3: Product: USB Receiver
desktop kernel: usb 1-3: Manufacturer: Logitech
desktop kernel: ata2: SATA link down (SStatus 0 SControl 330)
desktop kernel: tsc: Refined TSC clocksource calibration: 4291.933 MHz
desktop kernel: clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x3ddd9e7c8e4, max_idle_ns: 440795275179 ns
desktop kernel: clocksource: Switched to clocksource tsc
desktop kernel: usb 1-6: new full-speed USB device number 3 using xhci_hcd
desktop kernel: ata3: SATA link down (SStatus 0 SControl 330)
desktop kernel: thunderbolt 0-3: new device found, vendor=0x1 device=0x801f
desktop kernel: thunderbolt 0-3: Apple Inc. Studio Display
desktop kernel: usb 1-6: New USB device found, idVendor=0489, idProduct=e10d, bcdDevice= 0.01
desktop kernel: usb 1-6: New USB device strings: Mfr=0, Product=0, SerialNumber=0
desktop kernel: thunderbolt 0000:7a:00.0: 0:11 <-> 3:11 (DP): not enough bandwidth
desktop kernel: thunderbolt 0000:7a:00.0: 3:11: DP tunnel activation failed, aborting

Logs (from journalctl -b -1):

desktop kernel: xhci_hcd 0000:4b:00.0: xHCI host controller not responding, assume dead
desktop kernel: xhci_hcd 0000:4b:00.0: HC died; cleaning up
desktop kernel: usb usb5-port1: couldn't allocate usb_device
desktop kernel: thunderbolt 0-3: new device found, vendor=0x1 device=0x801f
desktop kernel: thunderbolt 0-3: Apple Inc. Studio Display
desktop kernel: thunderbolt 0000:7a:00.0: 0:11 <-> 3:11 (DP): not enough bandwidth
desktop kernel: thunderbolt 0000:7a:00.0: 3:11: DP tunnel activation failed, aborting
desktop kernel: amdgpu 0000:7b:00.0: [drm] *ERROR* lttpr_caps phy_repeater_cnt is 0x0, forcing it to 0x80
desktop kernel: pcieport 0000:4a:04.0: Unable to change power state from D3hot to D0, device inaccessible

Hardware Details:

$ lspci -k | grep -EA3 'VGA|3D|Display'
03:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Navi 48 [RX 9070/9070 XT] (rev c0)
       Subsystem: Gigabyte Technology Co., Ltd Device 2424
       Kernel driver in use: amdgpu
       Kernel modules: amdgpu
--
7b:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Granite Ridge [Radeon Graphics] (rev c9)
       Subsystem: Gigabyte Technology Co., Ltd Device d000
       Kernel driver in use: amdgpu
       Kernel modules: amdgpu

$ boltctl list
● Apple Inc. Studio Display
  ├─ type:          peripheral
  ├─ name:          Studio Display
  ├─ vendor:        Apple Inc.
  ├─ uuid:          c9030000-0072-741e-03e6-fed950758808
  ├─ generation:    Thunderbolt 3
  ├─ status:        connected
  │  ├─ domain:     a38d4c17-007f-3439-ffff-ffffffffffff
  │  ├─ rx speed:   20 Gb/s = 2 lanes * 10 Gb/s
  │  ├─ tx speed:   20 Gb/s = 2 lanes * 10 Gb/s

What I’ve Tried:

  • Checked logs, which point to Thunderbolt bandwidth issues (DP tunnel activation failed) and xHCI controller failure.
  • Tried kernel parameters pcie_port_pm=off pcie_aspm=off with no effect.
  • Unplugging and plugging the display does not work
2

Please note I have no apple products in front of me, but others have used this on /etc/default/grub

GRUB_CMDLINE_LINUX="nouveau.modeset=0"

Then update grub=sudo update grub Reboot.
Any better?

Also, Ubuntu users may encounter Thunderbolt bandwidth issues, particularly with DP tunnel activation failures, and xHCI (Extended Host Controller Interface) controller problems. These issues can arise when using Thunderbolt docks or hubs, leading to problems like no video output on Thunderbolt monitors.

One reported issue involves AMD Rembrandt processors where DP tunneling fails with Thunderbolt monitors, resulting in no video output on external monitors despite the system detecting the monitor and being able to change display modes.

Regarding xHCI controller issues, some users have experienced difficulties with USB bandwidth and host controller resources, which can affect USB 2.0 devices.
In some cases, disabling xHCI in the BIOS can resolve these issues, but this may also disable all USB3 controllers.

To address DP tunneling failures, updates to the Linux kernel have been applied to fix DP tunneling with Thunderbolt monitors.
For xHCI issues, users might consider disabling xHCI in the BIOS, though this is not always an option in newer BIOS versions.