A GNOME Shell (46+) Quick Settings extension for four fixed CPU energy-performance-preference (EPP) states:
| Mode | EPP | platform_profile |
|---|---|---|
| Power Saver | power |
low-power |
| Balanced-Saver | balance_power |
low-power |
| Balanced-Performance | balance_performance |
balanced |
| Performance | performance |
performance |
platform_profile only has three tiers against four EPP levels;
Balanced-Saver shares the low-power tier with Power Saver rather than
with Balanced-Performance, because on ThinkPad DYTC hardware
platform_profile — not EPP — drives the fan curve. EPP is the finer knob
within that shared tier.
Plus a Lock switch that blocks automatic (firmware/ACPI-hotkey) drift
without affecting manual selection, and a battery safety net that
enforces at least Balanced-Saver below 20% while discharging, unaffected
by Lock. A manually selected Power Saver remains active. Toggling Lock
keeps the menu open and stores the policy immediately. If the next enforcement
attempt fails, Lock is disabled again instead of claiming protection that the
hardware could not provide.
Successor to
power-saver-epp-fix;
see PLAN.md for the full design rationale.
The tile reads every available CPU EPP value directly from sysfs. It refreshes
after local changes, when the menu opens and every five seconds, so external
EPP changes are visible even with Lock disabled. The four exact values map
directly to the four modes above. Conflicting CPU values are shown as
Mixed; unreadable or unsupported EPP values as Unknown.
On systems without a platform_profile interface, EPP works independently.
When the interface is available, the helper verifies that EPP and platform
profile stay consistent. With Lock enabled, drift is reverted. With Lock
disabled, external platform drift is adopted: balanced maps to
Balanced-Performance; low-power maps to Power Saver unless the CPUs
already expose balance_power, in which case it maps to Balanced-Saver.
On newer kernels, provider-specific interfaces below
/sys/class/platform-profile/ are authoritative for reading and verification.
The helper prefers the legacy /sys/firmware/acpi/platform_profile aggregate
as the kernel-coordinated write path and falls back to direct provider writes
only when that aggregate is unavailable or rejects the request. On some
ThinkPad DYTC firmware, a platform_profile write can be silently rejected
regardless of AC/battery state or proximity to the preceding EPP/PPD writes
(see
docs/power-saver-platform-profile-diagnose.de.md
for the measurement behind this). Rather than fail the whole mode change over
that, the helper treats an unconfirmed platform profile as pending: EPP and
power-profiles-daemon stay in effect, the tile still shows the selected
mode, a Platform profile pending row appears in the menu, and the
background reassert keeps retrying (rate-limited to avoid hammering the
firmware) until the hardware confirms.
The installer keeps power-profiles-daemon active but restarts it with its
platform_profile driver blocked, using the guard proven by
power-saver-epp-fix. The helper first selects PPD's matching coarse profile,
waits for its CPU write, then applies and verifies the exact EPP and platform
state above. Uninstalling removes the guard and restarts PPD normally.
bash install.shInstalls a root helper to /usr/local/bin/eppmode-helper, a
passwordless sudoers rule scoped to that single binary
(/etc/sudoers.d/eppmode), and systemd units for boot restore, lock
drift-reassertion and the battery safety-net poll. Requires sudo.
bash uninstall.shRemoves the helper, sudoers rule, systemd units, udev rule and state directory. Remove the GNOME Shell extension itself separately, e.g.:
gnome-extensions uninstall eppmode@yurij.deEnglish (source), German and Spanish. To regenerate po/eppmode.pot
and rebuild the compiled .mo files after editing extension.js or a
.po file:
tools/build-locale.shGPL-3.0-or-later, see LICENSE.