Update: I performed an extensive diagnostic test on my iMac 27" (2017), equipped with an AMDGPU graphics card and a Cirrus Logic CS8409 audio chip, running Ubuntu 24.04.2 LTS with Wayland.
System configuration: OS: Ubuntu 24.04.2 LTS, Wayland Kernel: 6.11.0-29-generic Graphics: AMDGPU 25.10.1 (official driver from AMD) Audio: CS8409, compiled manually from GitHub Findings: ALSA detects the CS8409 as card 0 (aplay -l), and the device works properly. PipeWire correctly recognizes the mixer and nodes (pw-dump confirms CS8409/CS42L83 detection). PulseAudio lists the output as alsa_output.pci-0000_00_1f.3.analog- stereo, driven via PipeWire and using the CS8409 mixer. The kernel module snd_hda_codec_cs8409 is loaded (lsmod), and dmesg confirms autoconfiguration for line outs, headphone outs, and internal mics. The system has the latest headers installed: linux- headers-6.11.0-29-generic and linux-headers-generic-hwe-24.04, matching the active kernel — no legacy packages were needed. Note: The CS8409 driver must be compiled manually and breaks after kernel updates unless recompiled. This clearly shows the need to integrate the driver into either alsa-ucm-conf or the mainline Linux kernel. Modern Ubuntu systems are fully capable of supporting it without older headers — the only missing piece is native module inclusion. Additional note (graphics): To ensure proper graphical performance on iMac 27" (2017) with AMD Radeon GPUs, I highly recommend that AMDGPU drivers be prioritized in kernel-level integration. When I installed AMDGPU 25.10.1 for Ubuntu 24.04.2, the system instantly detected native 5K resolution without any manual configuration. Mesa fallback drivers caused incorrect resolution detection and had a negative impact on audio subsystem behavior. Using AMDGPU significantly improves both graphical and system stability. Recommendation: Please consider adding native support for the CS8409 codec into alsa-ucm-conf or the Linux kernel. Additionally, prioritize AMDGPU over Mesa drivers when detecting Apple hardware during OS setup. These changes would ensure reliable functionality across graphics and audio systems for affected users. Thank you for your work! -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2114760 Title: Missing drivers for Cirrus Logic CS8409 and AMDGPU on iMac 27" (2017) 5K To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/2114760/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
