Public bug reported:
Note: I used Claude to help analyze the logs, identify the faulty
package, and write this report. I applied the workaround and verified
the results on my machine.
I can help if you need me to reproduce something later.
== Summary ==
After upgrading linux-firmware-amd-graphics from 20240318.git3b128b60-0ubuntu3.3
to 20240318.git3b128b60-0ubuntu3.4 (apt upgrade, 2026-11-04), the display
microcontroller firmware (DMUB) for DCN 4.0.1 fails to load on an AMD
Radeon RX 9070 XT GPU (PCI ID 1002:7550, rev c0, Sapphire subsystem 1da2:e491).
The PSP rejects the
firmware, and the kernel then logs "DMCUB error - collecting diagnostic data"
continuously (over 1100 times in about 7 minutes). The display is unusable.
Downgrading to linux-firmware 20240318.git3b128b60-0ubuntu2.26 (monolithic
package) fixes the problem: a different DMUB firmware version loads cleanly.
== System ==
- Ubuntu 24.04.5 LTS
- Kernel: 7.0.0-42-generic (Ubuntu 7.0.0-42.42~24.04.1-generic 7.0.14)
- GPU: AMD Radeon RX 9070 XT (Sapphire)
28:00.0 VGA compatible controller [0300]: AMD/ATI Device [1002:7550] (rev c0)
DCN 4.0.1, 16 GB GDDR6
- Kernel cmdline: quiet splash pcie_aspm=off amdgpu.sg_display=0
amdgpu.dcdebugmask=0
== Broken (linux-firmware-amd-graphics 0ubuntu3.4) ==
amdgpu 0000:28:00.0: [drm] Loading DMUB firmware via PSP: version=0x07002F00
amdgpu 0000:28:00.0: failed to load ucode DMCUB(0x3F)
amdgpu 0000:28:00.0: psp gfx command LOAD_IP_FW(0x6) failed and response status
is (0x11)
amdgpu 0000:28:00.0: [drm] Display Core v3.2.369 initialized on DCN 4.0.1
amdgpu 0000:28:00.0: [drm] Wait for DMUB auto-load failed: 3
amdgpu 0000:28:00.0: [drm] DMUB hardware initialized: version=0x07002F00
amdgpu 0000:28:00.0: [drm] *ERROR* dc_dmub_srv_log_diagnostic_data: DMCUB error
- collecting diagnostic data
(the last line repeats 1114 times)
The SMU, VCN, MES and GFX blocks all initialize normally. Only the
display firmware fails.
== Working (linux-firmware 0ubuntu2.26) ==
amdgpu 0000:28:00.0: [drm] Loading DMUB firmware via PSP: version=0x0A000400
amdgpu 0000:28:00.0: [drm] DMUB hardware initialized: version=0x0A000400
No DMCUB errors.
== Analysis ==
0ubuntu3.4 ships a DMUB firmware for DCN 4.0.1 (dcn_4_0_1_dmcub.bin) with
version 0x07002F00. That version is older than the 0x0A000400 that works.
The PSP refuses to load it (status 0x11). This looks like a regression or a
wrong firmware blob in the 0ubuntu3.4 update for DCN 4.0.1.
Note that the other firmwares are NEWER in the broken setup (SMU 104.76.0
vs 104.74.0, VCN ENC 1.12 vs 1.4), while the DMUB is OLDER (0x07002F00 vs
0x0A000400). The rest of the package was updated, but the DCN 4.0.1 DMUB
blob looks mismatched (older, or possibly signed for a different PSP).
== Steps to reproduce ==
1. On a system with an RX 9070 XT GPU (1002:7550), install
linux-firmware-amd-graphics 20240318.git3b128b60-0ubuntu3.4 and run
update-initramfs.
2. Reboot.
3. Check journalctl -k: DMCUB(0x3F) fails to load, followed by repeated DMCUB
errors.
== Workaround ==
sudo apt install linux-firmware=20240318.git3b128b60-0ubuntu2.26
sudo apt-mark hold linux-firmware
== Attachments ==
minimal.txt contains:
- Hardware and software: GPU (with VBIOS version), motherboard and BIOS,
OS, kernel, and kernel command line
- dpkg history for the linux-firmware packages (upgrade to 0ubuntu3.4,
then downgrade to 0ubuntu2.26)
- Key amdgpu lines from the failing boot (0ubuntu3.4): DMUB, PSP, SMU and
VCN firmware versions, the load failure, the first DMCUB errors, and how
many times they repeat
- The same lines from the working boot (0ubuntu2.26)
The full kernel logs for both boots (anonymized) are available on
request.
** Affects: linux-firmware (Ubuntu)
Importance: Undecided
Status: New
** Attachment added: "minimal.txt"
https://bugs.launchpad.net/bugs/2173166/+attachment/6015216/+files/minimal.txt
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https://bugs.launchpad.net/bugs/2173166
Title:
linux-firmware-amd-graphics 20240318.git3b128b60-0ubuntu3.4: DCN 4.0.1
DMUB firmware rejected by PSP (LOAD_IP_FW status 0x11) on RX 9070
[1002:7550], display broken
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