Public bug reported:
After `apt upgrade` bumped linux-firmware-amd-graphics from
20240318.git3b128b60-0ubuntu3.3 to ...0ubuntu3.4 (noble-updates/main), my
discrete Radeon at PCI 03:00.0 ([1002:7550], DCN 4.0.1) black-screens shortly
after gdm starts. The machine boots and stays reachable over SSH, so this is a
display-engine failure, not a full hang. Downgrading the package back to 3.3
fixes it completely.
This looks like a firmware regression: the 3.4 package ships a dcn_4_0_1 DMCUB
blob that the GPU's PSP refuses to load. The DMUB version the kernel loads for
this device actually goes *backwards* between the two packages:
fw 3.3 (works): Loading DMUB firmware via PSP: version=0x0A000800 ->
initializes, display works
fw 3.4 (broken): Loading DMUB firmware via PSP: version=0x07002F00 -> PSP
rejects it, display dead
On 3.4 the load fails and the display engine never comes up:
amdgpu 0000:03:00.0: amdgpu: failed to load ucode DMCUB(0x3D)
amdgpu 0000:03:00.0: amdgpu: psp gfx command LOAD_IP_FW(0x6) failed and
response status is (0x11)
amdgpu 0000:03:00.0: amdgpu: [drm] Wait for DMUB auto-load failed: 3
amdgpu 0000:03:00.0: [drm] *ERROR* dc_dmub_srv_log_diagnostic_data: DMCUB
error - collecting diagnostic data
amdgpu 0000:03:00.0: [drm] *ERROR* Error queueing DMUB command: status=2
Those last two then repeat thousands of times (7373 *ERROR* lines for 03:00.0 in
a single boot). On 3.3 there are zero DMCUB errors.
ProblemType: Bug
DistroRelease: Ubuntu 24.04
Package: linux-firmware 20240318.git3b128b60.0ubuntu3.1
ProcVersionSignature: Ubuntu 6.17.0-40.40~24.04.1-generic 6.17.13
Uname: Linux 6.17.0-40-generic x86_64
ApportVersion: 2.28.3-0ubuntu0.1
Architecture: amd64
CRDA: N/A
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Sat Nov 7 06:23:54 2026
InstallationDate: Installed on 2026-01-15 (296 days ago)
InstallationMedia: Ubuntu 24.04.3 LTS "Noble Numbat" - Release amd64
(20250805.1)
MachineType: System76 Thelio Mira
PackageArchitecture: all
ProcFB: 0 amdgpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-6.17.0-40-generic
root=UUID=fa745f42-36cd-4c85-8bd8-cdae1890ad40 ro kvm.enable_virt_at_load=0
quiet splash vt.handoff=7
RelatedPackageVersions:
linux-restricted-modules-6.17.0-40-generic N/A
linux-backports-modules-6.17.0-40-generic N/A
linux-firmware 20240318.git3b128b60.0ubuntu3.1
SourcePackage: linux-firmware
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 06/16/2025
dmi.bios.release: 5.35
dmi.bios.vendor: American Megatrends International, LLC.
dmi.bios.version: 3.25.SP02
dmi.board.asset.tag: Default string
dmi.board.name: Thelio Mira
dmi.board.vendor: System76
dmi.board.version: thelio-mira-r4
dmi.chassis.asset.tag: Default string
dmi.chassis.type: 3
dmi.chassis.vendor: System76
dmi.chassis.version: thelio-mira-r4
dmi.modalias:
dmi:bvnAmericanMegatrendsInternational,LLC.:bvr3.25.SP02:bd06/16/2025:br5.35:svnSystem76:pnThelioMira:pvrthelio-mira-r4:rvnSystem76:rnThelioMira:rvrthelio-mira-r4:cvnSystem76:ct3:cvrthelio-mira-r4:skuDefaultstring:
dmi.product.family: Default string
dmi.product.name: Thelio Mira
dmi.product.sku: Default string
dmi.product.version: thelio-mira-r4
dmi.sys.vendor: System76
** Affects: linux-firmware (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug noble wayland-session
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https://bugs.launchpad.net/bugs/2173629
Title:
linux-firmware-amd-graphics 3.4 ships a regressed dcn_4_0_1 DMCUB blob
that black-screens Radeon [1002:7550] (DCN 4.0.1) at gdm
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