Public bug reported:
Since upgrading linux-firmware-amd-graphics from 20240318.git3b128b60-0ubuntu3.3
to 0ubuntu3.4 (SRU for LP: #2168847), the desktop freezes briefly every few
seconds on an RDNA4 GPU. The kernel log is flooded with:
amdgpu 0000:2f:00.0: [drm] *ERROR* Error queueing DMUB command: status=2
amdgpu 0000:2f:00.0: [drm] *ERROR* dc_dmub_srv_log_diagnostic_data: DMCUB
error - collecting diagnostic data
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. DCN 4.0.1 (RDNA4) GPUs therefore load the
DCN 3.2 (RDNA3) DMCUB firmware. In 0ubuntu3.3 the file is a regular dcn401 blob.
Loaded DMUB firmware version:
- 0ubuntu3.3: version=0x0A000800
- 0ubuntu3.4: version=0x07002F00
Evidence:
- Last boot with 0ubuntu3.3: 0 DMUB errors
- First boot with 0ubuntu3.4: 351 DMUB errors in ~4 minutes
- After downgrading to 0ubuntu3.3: DMUB version back to 0x0A000800,
0 errors in ~26 minutes, stalls gone
This likely affects all RDNA4 users on noble with the HWE kernel.
System:
- GPU: 2f:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc.
[AMD/ATI] Device [1002:7590] (rev c0)
- Kubuntu 24.04 LTS, kernel 7.0.0-42-generic (HWE)
- Mesa 25.2.8-0ubuntu0.24.04.4
- Session: wayland
Workaround: downgrade to 0ubuntu3.3 and apt-mark hold linux-firmware-
amd-graphics.
Attached: kernel logs for both firmware versions and after downgrade,
ls output showing the symlink.
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: pass
CurrentDesktop: KDE
Date: Fri Nov 6 15:13:03 2026
Dependencies:
InstallationDate: Installed on 2023-03-09 (1338 days ago)
InstallationMedia: Kubuntu 22.04.2 LTS "Jammy Jellyfish" - Release amd64
(20230223)
PackageArchitecture: all
SourcePackage: linux-firmware-amd-graphics
UpgradeStatus: Upgraded to noble on 2024-09-15 (782 days ago)
** Affects: linux-firmware-amd-graphics (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug noble wayland-session
** Attachment added: "firmware-symlink-0ubuntu3.4.txt"
https://bugs.launchpad.net/bugs/2173546/+attachment/6015441/+files/firmware-symlink-0ubuntu3.4.txt
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https://bugs.launchpad.net/bugs/2173546
Title:
[regression] linux-firmware-amd-graphics 0ubuntu3.4: dcn_4_0_1_dmcub
symlinked to DCN 3.2 firmware, DMUB errors and display stalls on RDNA4
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