[Bug 2164686] [NEW] AMD Mullins/Kabini APU incorrectly defaults to radeon instead of amdgpu

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 -- You received this bug notification because you are subscribed to linux in Ubuntu. Matching subscriptions: Bgg, Bmail, Nb https://bugs.launchpad.net/bugs/2164686 Title: AMD Mullins/Kabini APU incorrectly defaults to radeon instead of amdgpu Status in linux package in Ubuntu: New Bug description: 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.) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2164686/+subscriptions