Thinkpad 2nd fan patch hack for Linux Kernel 5.13. Forces 2nd fan detection and control. Use at your own risk! (confirmed to work on P15 Gen2)

thinkpad_acpi.patch

--- drivers/platform/x86/thinkpad_acpi.c.bak    2021-06-28 00:21:11.000000000 +0200
+++ drivers/platform/x86/thinkpad_acpi.c        2022-05-18 04:07:06.814390699 +0200
@@ -8883,31 +8883,22 @@
        quirks = tpacpi_check_quirks(fan_quirk_table,
                                     ARRAY_SIZE(fan_quirk_table));

-       if (gfan_handle) {
-               /* 570, 600e/x, 770e, 770x */
-               fan_status_access_mode = TPACPI_FAN_RD_ACPI_GFAN;
-       } else {
-               /* all other ThinkPads: note that even old-style
-                * ThinkPad ECs supports the fan control register */
-               if (likely(acpi_ec_read(fan_status_offset,
-                                       &fan_control_initial_status))) {
-                       fan_status_access_mode = TPACPI_FAN_RD_TPEC;
-                       if (quirks & TPACPI_FAN_Q1)
-                               fan_quirk1_setup();
-                       if (quirks & TPACPI_FAN_2FAN) {
-                               tp_features.second_fan = 1;
-                               pr_info("secondary fan support enabled\n");
-                       }
-                       if (quirks & TPACPI_FAN_2CTL) {
-                               tp_features.second_fan = 1;
-                               tp_features.second_fan_ctl = 1;
-                               pr_info("secondary fan control enabled\n");
-                       }
-               } else {
-                       pr_err("ThinkPad ACPI EC access misbehaving, fan status and control unavailable\n");
-                       return 1;
-               }
-       }
+  /*
+   * Force 2nd fan control hack
+   *
+   * Do not apply for 570, 600e/x, 770e, 770x
+   */
+  if (likely(acpi_ec_read(fan_status_offset,
+        &fan_control_initial_status))) {
+    fan_status_access_mode = TPACPI_FAN_RD_TPEC;
+    fan_quirk1_setup();
+    tp_features.second_fan = 1;
+    tp_features.second_fan_ctl = 1;
+    pr_info("secondary fan control enabled\n");
+  } else {
+    pr_err("ThinkPad ACPI EC access misbehaving, fan status and control unavailable\n");
+    return 1;
+  }

        if (sfan_handle) {
                /* 570, 770x-JL */