From bb58347c93148e906949efa7c633de124759f118 Mon Sep 17 00:00:00 2001
From: Sergei Poljanski <me@asxp.io>
Date: Fri, 16 Oct 2026 05:41:33 +0400
Subject: [PATCH] power: allow manual fan control on the ThinkPad

thinkpad_acpi ignores writes to /proc/acpi/ibm/fan unless loaded
with fan_control=1. Enable it so the fan can be set to a level (0-7)
or full-speed by hand; the firmware stays in charge while the level
is "auto". Applies from the next boot or a reload of the module.

Assisted-by: Claude:opus-5
---
 modules/power.nix | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/modules/power.nix b/modules/power.nix
index a3216ff..7a64090 100644
--- a/modules/power.nix
+++ b/modules/power.nix
@@ -10,6 +10,10 @@
   # on P14s G6 AMD. See https://lore.kernel.org/all/ZnFYpWHJ5Ml724Nv@ohnotp/
   boot.kernelParams = [ "amd_pstate=active" "resume_offset=1769472" "acpi.ec_no_wakeup=1" ];
 
+  # Allow manual fan control via /proc/acpi/ibm/fan (level 0-7, auto,
+  # full-speed). Firmware stays in charge while level is "auto".
+  boot.extraModprobeConfig = "options thinkpad_acpi fan_control=1";
+
   # Hibernate / resume from encrypted swapfile on LUKS root.
   # P14s G6 AMD has no S3 (Modern Standby only); this enables
   # suspend-then-hibernate so long sleeps drain to disk.