battery_life/docs/tlp-configuration.md

TLP Configuration Guide

Overview

TLP (Linux Advanced Power Management) is a feature-rich command line utility for optimizing battery life on Linux laptops. This guide explains the key configuration options and their impact on battery performance.

Configuration File Location

The main configuration file is located at:

• /etc/tlp.conf (system-wide configuration)
• Backup copies are created as /etc/tlp.conf.backup.YYYYMMDD_HHMMSS

Key Configuration Sections

1. Operation Modes

# Default operation mode
TLP_DEFAULT_MODE=BAT

# Use persistent mode for consistent behavior
TLP_PERSISTENT_DEFAULT=0

Explanation:

• BAT: Optimizes for battery life
• AC: Optimizes for AC power (performance)
• DEF: Uses kernel defaults

2. CPU Power Management

# CPU frequency governor
CPU_SCALING_GOVERNOR_ON_AC=powersave
CPU_SCALING_GOVERNOR_ON_BAT=powersave

# CPU frequency limits
CPU_SCALING_MIN_FREQ_ON_BAT=800000
CPU_SCALING_MAX_FREQ_ON_BAT=1600000

# Intel P-state settings
CPU_HWP_ON_BAT=power
CPU_MAX_PERF_ON_BAT=50
CPU_BOOST_ON_BAT=0

Impact:

• Reduces CPU power consumption by 20-40%
• May slightly reduce performance under heavy loads
• Automatic scaling based on demand

3. Disk Power Management

# Advanced Power Management levels
DISK_APM_LEVEL_ON_BAT="128 128"

# IO scheduler optimization
DISK_IOSCHED="mq-deadline mq-deadline"

# AHCI Link Power Management
AHCI_ALPM_ON_BAT=min_power

Impact:

• Reduces disk power consumption
• May increase disk access latency slightly
• Significant savings for HDDs, moderate for SSDs

4. Graphics Power Management

# Radeon settings (for AMD GPUs)
RADEON_POWER_PROFILE_ON_BAT=low
RADEON_DPM_STATE_ON_BAT=battery

# Intel graphics automatically managed

Impact:

• Reduces GPU power consumption by 15-30%
• Lower graphics performance in games/3D applications
• Minimal impact on desktop usage

5. Wireless Device Management

# WiFi power saving
WIFI_PWR_ON_BAT=on

# Bluetooth management
DEVICES_TO_DISABLE_ON_BAT="bluetooth"

# Wake on LAN
WOL_DISABLE=Y

Impact:

• Reduces wireless power consumption
• May affect network performance slightly
• Automatic reconnection when needed

6. USB Power Management

# Enable USB autosuspend
USB_AUTOSUSPEND=1

# Exclude critical devices
USB_BLACKLIST_PRINTER=1
USB_BLACKLIST_PHONE=0

Impact:

• Suspends unused USB devices
• Saves 0.5-2W per device
• Blacklist prevents issues with specific devices

7. Battery Charge Thresholds (ThinkPad)

# Start charging at 75%
START_CHARGE_THRESH_BAT0=75

# Stop charging at 80%
STOP_CHARGE_THRESH_BAT0=80

Impact:

• Extends battery lifespan significantly
• Reduces available capacity slightly
• Optimal for plugged-in usage

Advanced Optimizations

CPU Undervolting

For advanced users, CPU undervolting can provide additional power savings:

# EXPERIMENTAL - Use with caution
# PHC_CONTROLS="F:V F:V F:V F:V"

Warning: Only use if you understand the risks. Incorrect values can cause system instability.

Custom Scripts

You can add custom power management commands to:

• /etc/tlp.d/ - Additional configuration files
• Systemd services for startup optimizations

Monitoring Configuration Impact

Check Current Settings

# Show all TLP settings
sudo tlp-stat

# Show specific components
sudo tlp-stat -p  # Processor
sudo tlp-stat -d  # Disks
sudo tlp-stat -g  # Graphics
sudo tlp-stat -u  # USB

Measure Power Consumption

# Before configuration changes
sudo powertop --time=60

# Apply changes
sudo tlp start

# After configuration changes
sudo powertop --time=60

Distribution-Specific Notes

Ubuntu/Debian

• Install with: sudo apt install tlp tlp-rdw
• May conflict with power-profiles-daemon

Fedora/RHEL

• Install with: sudo dnf install tlp tlp-rdw
• Disable conflicting services

Arch Linux

• Install with: sudo pacman -S tlp
• Enable service: sudo systemctl enable tlp.service

Laptop-Specific Optimizations

ThinkPad

• Install additional tools: tp-smapi-dkms acpi-call-dkms
• Battery threshold support available
• Enhanced fan control

Dell

• Use i8kutils for fan control
• BIOS settings may override some options

HP

• Limited hardware support
• Focus on software optimizations

Troubleshooting

Common Issues

1. TLP not applying settings

   sudo systemctl enable tlp.service
   sudo systemctl start tlp.service
   

2. Settings reset after reboot

   • Check if other power managers are active
   • Ensure TLP service is enabled

3. USB devices not working

   • Add device IDs to blacklist
   • Check lsusb output for device identification

Verification Commands

# Check TLP service status
systemctl status tlp.service

# Verify configuration syntax
sudo tlp-stat -c

# Test specific settings
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

Performance vs Battery Life

Maximum Battery Life Profile

• All power saving features enabled
• Significant performance reduction acceptable
• Target: 30-50% longer battery life

Balanced Profile

• Moderate power saving
• Minimal performance impact
• Target: 15-25% longer battery life

Performance Profile

• Limited power saving
• Maximum performance preserved
• Target: 5-10% longer battery life

Regular Maintenance

Monthly Tasks

• Review power consumption reports
• Check battery health
• Update TLP configuration if needed

After System Updates

• Verify TLP service is still running
• Check for configuration file changes
• Test critical functionality

Best Practices

1. Start Conservative: Begin with moderate settings and adjust gradually
2. Monitor Impact: Use PowerTOP to measure actual improvements
3. Document Changes: Keep track of modifications for troubleshooting
4. Test Thoroughly: Verify all hardware functions correctly
5. Regular Updates: Keep TLP and related tools current

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This configuration guide should be used alongside the main installation and monitoring tools provided in this repository.