Public bug reported:
Bug Report: AMD Mullins/Kabini APU incorrectly defaults to radeon
instead of amdgpu
Summary
On Ubuntu 24.04 (kernel 7.0.0-30-generic), my Lenovo system with an AMD
Mullins/Kabini APU consistently defaults to the legacy radeon driver. This
hardware fully supports amdgpu, and switching to amdgpu results in immediate
and significant stability improvements, including correct multi-monitor
behaviour and stable GPU acceleration in Chromium-based applications. This
suggests the driver-selection heuristics for Sea Islands (CIK) hardware may
need updating. My subsystem ID (17aa:369a) may be missing from the
amdgpu-preferred list.
Hardware
- Model: Lenovo desktop
- GPU: AMD Mullins / Radeon R4/R5 Graphics
- PCI ID: 1002:9851
- Subsystem: 17aa:369a
- Generation: Sea Islands (CIK)
Incorrect default behaviour
On a clean Ubuntu install, the system binds the GPU to the legacy radeon driver:
lspci -nnk | grep -A3 VGA
Kernel driver in use: radeon
Kernel modules: radeon, amdgpu
Using radeon causes:
- GPU process crashes in Chrome/Chromium
- flickering and corrupted text input
- unstable multi-monitor behaviour
- degraded performance in Electron apps
- fallback to software rendering in some cases
Correct behaviour after manual override
After enabling amdgpu and disabling radeon via kernel parameters:
amdgpu.si_support=1 amdgpu.cik_support=1 radeon.si_support=0
radeon.cik_support=0
and blacklisting radeon, the system boots with:
Kernel driver in use: amdgpu
Kernel modules: radeon, amdgpu
Chrome’s GPU diagnostics confirm stable hardware acceleration:
- Canvas: Hardware accelerated
- Compositing: Hardware accelerated
- WebGL: Hardware accelerated
- GPU process crash count: 0
Multi-monitor output also becomes stable.
Evidence from chrome://gpu
Representative lines:
GL_RENDERER: ANGLE (AMD Radeon R5 Graphics … Mesa 26.0.8)
GPU process crash count: 0
This demonstrates that amdgpu + Mesa 26 is fully functional on this
hardware.
Kernel logs
dmesg shows amdgpu initialising:
amdgpu: Virtual CRAT table created for CPU
amdgpu: Topology: Add CPU node
This indicates the module loads correctly but is not selected by
default.
Expected behaviour
Ubuntu should bind Mullins/Kabini APUs to amdgpu by default when:
- the hardware supports it
- the module loads cleanly
- the modern driver provides significantly better stability
This may require:
- adding subsystem ID 17aa:369a to amdgpu-preferred lists
- adjusting SI/CIK detection heuristics
- updating documentation for Mullins/Kabini users
Request
Please evaluate whether this Lenovo Mullins/Kabini device should default to
amdgpu rather than radeon, and whether the driver-selection rules for Sea
Islands hardware need updating. I am happy to provide full logs, kernel dumps,
or run additional tests if needed.
(This report was generated with the assistance of Microsoft Copilot
after investigating persistent Chrome flickering and keyboard input
corruption on this hardware. Firefox was unaffected. I don’t claim to
fully understand the underlying driver behaviour, but the evidence above
reflects the results of the investigation.)
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Attachment added: "Chrome's about-gpu report after deploying fix."
https://bugs.launchpad.net/bugs/2164686/+attachment/5993968/+files/about-gpu-2026-08-20T20-30-40-717Z.txt
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https://bugs.launchpad.net/bugs/2164686
Title:
AMD Mullins/Kabini APU incorrectly defaults to radeon instead of
amdgpu
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