01-thermal-setup.sh

Installs and configures mbpfan for proper fan control on the MacBook Air 2020. Without this script, the default thermald configuration does not drive the Apple SMC fan correctly — the CPU can sustain 97-100 °C at near-minimum fan speed.

Usage

sudo bash scripts/01-thermal-setup.sh [--dry-run] [--help]

Requires root. Run this immediately after installing CachyOS.

Flag	Description
--dry-run	Preview all actions without modifying the system
--help	Show usage information and exit

What It Does

1. Preflight — locates the Apple SMC sysfs path (applesmc or APP0001:00), displays current temperatures and fan speed
2. Install mbpfan — installs from the AUR via paru or yay (runs as the invoking user, not root)
3. Write config — creates /etc/mbpfan.conf with the fan curve below
4. Configure thermald — writes /etc/thermald/thermal-conf.xml limiting thermald to Intel RAPL power capping only (no fan control)
5. Enable services — restarts thermald with the new config, enables and starts mbpfan.service
6. Verify — displays fan speed, service status, and current temperatures

Fan Curve

Temperature	Fan Speed	Behaviour
Below 55 °C	2700 RPM	Near-silent idle
55-70 °C	2700-4500 RPM	Linear ramp (normal use)
70-85 °C	4500-6500 RPM	Aggressive ramp (heavy load)
Above 85 °C	8000 RPM	Maximum (thermal protection)

Hysteresis: fan speed does not reduce until the temperature drops 4 °C below the threshold (temp_change_factor = 4).

Files Modified

Path	Purpose
/etc/mbpfan.conf	Fan curve configuration
/etc/thermald/thermal-conf.xml	RAPL-only thermald config (no fan zones)

ACPI Path Detection

The script searches two locations for the Apple SMC fan interface:

1. /sys/devices/platform/applesmc* (standard path)
2. /sys/devices/LNXSYSTM:00/.../APP0001:00 (ACPI namespace fallback)

If neither is found, mbpfan still works — it reads temperature via coretemp sensors and controls the fan through its own kernel interface.

Prerequisites

• An AUR helper (paru or yay)
• lm_sensors (for the sensors verification command)

Source

View the full source on GitHub.