Public bug reported:
TITEL (ins Titelfeld):
dcn_4_0_1_dmcub.bin.zst symlink points to dcn_3_2_0_dmcub.bin.zst, DMCUB load
fails on RX 9070 XT
BESCHREIBUNG:
Package: linux-firmware-amd-graphics 20240318.git3b128b60-0ubuntu3.4
(noble-updates)
System: Linux Mint 22.3 (Ubuntu 24.04 noble base), kernel 7.0.0-42-generic
Hardware: AMD Radeon RX 9070 XT
Problem:
Regression: upgraded from 0ubuntu3.3 to 0ubuntu3.4 on 2026-11-05 via the update
manager.
With 0ubuntu3.3 dcn_4_0_1_dmcub.bin.zst was a regular file (367904 bytes
uncompressed);
with 0ubuntu3.4 the file
/lib/firmware/amdgpu/dcn_4_0_1_dmcub.bin.zst
is a symlink to dcn_3_2_0_dmcub.bin.zst:
lrwxrwxrwx 1 root root 23 Okt 19 13:08
/lib/firmware/amdgpu/dcn_4_0_1_dmcub.bin.zst -> dcn_3_2_0_dmcub.bin.zst
The kernel therefore loads the wrong DMCUB firmware (version 0x07002F00),
fails to load it, and then floods the log with DMCUB errors every second.
Boot before the workaround:
kernel: amdgpu 0000:03:00.0: [drm] Loading DMUB firmware via PSP:
version=0x07002F00
kernel: amdgpu 0000:03:00.0: failed to load ucode DMCUB(0x3F)
kernel: amdgpu 0000:03:00.0: [drm] Wait for DMUB auto-load failed: 3
kernel: amdgpu 0000:03:00.0: [drm] DMUB hardware initialized: version=0x07002F00
kernel: amdgpu 0000:03:00.0: [drm] *ERROR* dc_dmub_srv_log_diagnostic_data:
DMCUB error - collecting diagnostic data
(the last line repeats every second)
Workaround:
Place the original dcn_4_0_1_dmcub.bin in /lib/firmware/updates/amdgpu/ and run
update-initramfs -u.
The file is identical (md5 bc9e171a3214b34e64f7a4db3f40165f, 368288 bytes) to
amdgpu/dcn_4_0_1_dmcub.bin in upstream linux-firmware (git.kernel.org).
Boot after the workaround:
kernel: amdgpu 0000:03:00.0: [drm] Loading DMUB firmware via PSP:
version=0x0A005000
kernel: amdgpu 0000:03:00.0: [drm] DMUB hardware initialized: version=0x0A005000
No errors.
Expected: the symlink points to a matching dcn_4_0_1 firmware file.
** Affects: linux-firmware (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/2173333
Title:
dcn_4_0_1_dmcub.bin.zst symlink points to dcn_3_2_0_dmcub.bin.zst,
DMCUB load fails on RX 9070 XT
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