Getting AMD FirePro W5100 Working on Talos II with amdgpu

This post documents my working configuration for running an AMD FirePro W5100 on a Talos II POWER9 system using the amdgpu driver with Sway and multi-display support. After considerable testing, I've found a stable setup that handles LUKS encryption properly and drives multiple 4K displays.

Why the W5100?

The FirePro W5100 hits a practical sweet spot for POWER9 systems. It's the last generation before AMD introduced the Platform Security Processor (PSP) to their GPUs, avoiding another management engine layer. Among cards of its generation, it offers a solid combination of four DisplayPort outputs and a reasonable 50W TDP that doesn't require external power. Plus, AMD's open-source driver support is significantly better than NVIDIA's proprietary situation.

The Problem: radeon Driver on POWER9

By default, the W5100 loads the radeon driver on Linux, which causes significant issues on POWER9: kernel panics, display corruption, and general instability. The solution is to force the card to use the newer amdgpu driver instead, though this requires experimental support flags since the W5100 predates official amdgpu support.

Working Configuration

1. Kernel Parameters

Add these parameters to `/etc/default/grub`:

Parameter breakdown:

• • radeon.si_support=0 radeon.cik_support=0 — Disables radeon driver for SI/CIK cards
• • amdgpu.si_support=1 amdgpu.cik_support=1 — Enables amdgpu experimental support
• • amdgpu.dpm=1 — Enables dynamic power management
• • video=offb:off — Disables Open Firmware framebuffer
• • console=tty1 — Makes LUKS password prompt visible with amdgpu

2. Module Configuration

Create `/etc/modprobe.d/amdgpu.conf`:

# Blacklist radeon driver
blacklist radeon

# Force amdgpu to load for Cape Verde (W5100)
options amdgpu si_support=1
options amdgpu cik_support=1

3. LUKS Encryption Display Fix

Without the console=tty1 parameter, the LUKS password prompt becomes invisible when using amdgpu, showing only a floating cursor. This parameter redirects the console output properly, making the password prompt visible again.

4. Update initramfs and Reboot

sudo update-initramfs -u -k all
sudo update-grub
sudo reboot

Multi-Display Configuration with Sway

The W5100's four DisplayPort outputs work well with Sway. Here's a working configuration for multiple displays:

# ~/.config/sway/config

# Disable DPMS to prevent display sleep issues
exec swaymsg "output * dpms off"
exec swaymsg "output * power on"

# Example dual 4K display configuration
output DP-1 pos 0 0 resolution 3840x2160 scale 2
output DP-2 pos 1920 0 resolution 3840x2160 scale 2

# HiDPI scaling
output * scale 2

The DPMS disable commands prevent an issue where displays go dark and require cable reconnection to wake. This appears to be specific to the amdgpu/W5100/POWER9 combination.

Parameters to Avoid

Performance Notes

With this configuration, the W5100 performs adequately for desktop use. Video playback is smooth, Sway's effects work correctly, and the card handles multiple 4K displays without issue. The 4GB VRAM is sufficient for typical desktop workloads. At 50W TDP, the card runs cool and quiet without requiring additional cooling.

Stability Considerations

This configuration relies on experimental amdgpu support for SI/CIK cards, which may change with kernel updates. It's advisable to pin working kernels and maintain configuration backups. The setup has been stable in daily use, but kernel updates should be approached carefully.

Ara / アラ