Public bug reported:
After linux-firmware-amd-graphics was updated from
20240318.git3b128b60-0ubuntu3.3 to 20240318.git3b128b60-0ubuntu3.4, the
display on my AMD Radeon RX 9070 (Navi 48, DCN 4.0.1) stopped working
correctly.
Root cause:
In 0ubuntu3.4, /lib/firmware/amdgpu/dcn_4_0_1_dmcub.bin.zst is a symlink to
dcn_3_2_0_dmcub.bin.zst (the RX 7000 series / DCN 3.2.0 display firmware):
lrwxrwxrwx 1 root root 23 2026-10-19 08:08
/lib/firmware/amdgpu/dcn_4_0_1_dmcub.bin.zst -> dcn_3_2_0_dmcub.bin.zst
In 0ubuntu3.3 it is a real file:
-rw-r--r-- root/root 225553 2026-09-15 03:38
./lib/firmware/amdgpu/dcn_4_0_1_dmcub.bin.zst
Kernel log with 0ubuntu3.3 (works):
amdgpu 0000:03:00.0: [drm] Loading DMUB firmware via PSP: version=0x0A000800
amdgpu 0000:03:00.0: [drm] DMUB hardware initialized: version=0x0A000800
Kernel log with 0ubuntu3.4 (broken):
amdgpu 0000:03:00.0: [drm] Loading DMUB firmware via PSP: version=0x07002F00
amdgpu 0000:03:00.0: [drm] Wait for DMUB auto-load failed: 3
amdgpu 0000:03:00.0: [drm] DMUB hardware initialized: version=0x07002F00
followed by thousands of repeating:
amdgpu 0000:03:00.0: [drm] *ERROR* Error queuing DMUB command: status=2
amdgpu 0000:03:00.0: [drm] *ERROR* dc_dmub_srv_log_diagnostic_data: DMCUB
error - collecting diagnostic data
Symptoms:
- Black screen after the BIOS splash with two monitors connected
- Full-screen white/red/green/blue screens cycling on some boots
- With one monitor: GDM login screen appears, but graphical login loops back to
GDM (intermittently)
- Sluggish input in the desktop when login did succeed
Reproduced on kernels 7.0.0-42-generic and 7.0.0-38-generic (both HWE),
so it is not kernel-specific.
Workaround:
Downgrade to 0ubuntu3.3 (from Launchpad), apt-mark hold the package, and run
update-initramfs -u -k all. After this the RX 9070 loads DMUB firmware
0x0A000800 and there are zero DMUB errors across reboots with both monitors
connected.
System:
Ubuntu 24.04.5 LTS, GNOME 46 Wayland
GPU: AMD Radeon RX 9070 16 GB (PCI 03:00.0)
CPU: AMD Ryzen 7 7700X (iGPU at 12:00.0, unaffected)
Motherboard: Gigabyte B650M D3HPS
ProblemType: Bug
DistroRelease: Ubuntu 24.04
Package: linux-firmware-amd-graphics 20240318.git3b128b60-0ubuntu3.3
ProcVersionSignature: Ubuntu 7.0.0-42.42~24.04.1-generic 7.0.14
Uname: Linux 7.0.0-42-generic x86_64
ApportVersion: 2.28.3-0ubuntu0.1
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: ubuntu:GNOME
Date: Fri Nov 6 23:18:28 2026
Dependencies:
InstallationDate: Installed on 2025-12-08 (333 days ago)
InstallationMedia: Ubuntu 24.04.3 LTS "Noble Numbat" - Release amd64
(20250805.1)
PackageArchitecture: all
ProcEnviron:
LANG=en_US.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=xterm-256color
XDG_RUNTIME_DIR=<set>
SourcePackage: linux-firmware-amd-graphics
UpgradeStatus: No upgrade log present (probably fresh install)
** Affects: linux-firmware-amd-graphics (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug noble wayland-session
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https://bugs.launchpad.net/bugs/2173609
Title:
RX 9070: 0ubuntu3.4 symlinks dcn_4_0_1_dmcub to dcn_3_2_0 firmware,
DMUB failure and black screen
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