Sundar's Notes

Arch Linux Power Management

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Arch Linux Power Management

Comprehensive power management configuration for Arch Linux systems with Intel CPUs and integrated GPUs. Covers CPU governor tuning, GPU frequency limits, and hardware-accelerated video decoding.

Firefox GPU Acceleration and VAAPI

Enable GPU process in Firefox via about:config:

  • layers.gpu-process.enabled = true

For Intel Iris Xe GPUs, install the intel-media-driver package to enable VAAPI hardware decoding. Verify functionality with mpv to confirm VAAPI is working correctly.

Firefox flags for Wayland (typically defaults):

  • media.ffmpeg.vaapi.enabled = true
  • media.rdd-ffmpeg.enabled = true

Result: YouTube and streaming power usage decreases significantly when hardware decoding is active. See Firefox Teams configuration for related browser settings.

TLP Configuration with intel_pstate

Driver Mode

Configure TLP to use Intel HWP (Hardware P-states) in active mode:

CPU_DRIVER_OPMODE_ON_AC=active
CPU_DRIVER_OPMODE_ON_BAT=active

This is the preferred configuration for 11th, 12th, and 13th generation Intel CPUs.

CPU Governors

CPU_SCALING_GOVERNOR_ON_AC=performance
CPU_SCALING_GOVERNOR_ON_BAT=powersave

These settings take effect only when using HWP with intel_pstate in active mode.

Power Limits via Performance Percentage

CPU_MAX_PERF_ON_BAT=50
CPU_MIN_PERF_ON_BAT=0

This limits the CPU to approximately 50% of its available P-state range on battery, providing significant power savings.

Energy Performance Preference

CPU_ENERGY_PERF_POLICY_ON_BAT=power

Ensures maximum battery savings by prioritizing energy efficiency.

Intel GPU Frequency Limits

INTEL_GPU_MAX_FREQ_ON_BAT=900

Caps the Iris Xe GPU frequency for additional power savings during battery operation.

Disable cpupower Service

Since intel_pstate in active mode ignores cpupower frequency limits, disable the service to prevent conflicts:

sudo systemctl disable --now cpupower.service
sudo systemctl mask cpupower.service

Intel i915 Kernel Parameters

Fastboot

Reduces display initialization time:

  • i915.fastboot=1

Display C-States

Enables display power states for additional savings:

  • i915.enable_dc=2

Panel Self Refresh

Useful for laptops with PSR support. Not supported on all hardware, but worth documenting for future systems:

  • i915.enable_psr=1 — Conservative (default safe)
  • i915.enable_psr=2 — Force PSR2 if hardware supports it

PSR reduces GPU activity by allowing the panel to refresh itself when screen content is static.

Summary

  • Firefox uses hardware-accelerated video decoding via VAAPI
  • GPU process enabled, eliminating power-heavy software decoding
  • TLP tuned for intel_pstate active mode
  • CPU limited to 50% on battery for major power savings
  • Integrated GPU frequency capped
  • cpupower disabled to prevent conflicts
  • Intel i915 kernel parameters optimized for efficiency

This configuration significantly improves battery life during video playback, browsing, and general usage. Related to Nvidia GPU power management for hybrid graphics systems.

References

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