+/*
+ * Unitialized HFSP quirk: ACPI DSDT and EC fail to initialize the
+ * HFSP register at boot, so it contains 0x07 but the Thinkpad could
+ * be in auto mode (0x80).
+ *
+ * This is corrected by any write to HFSP either by the driver, or
+ * by the firmware.
+ *
+ * We assume 0x07 really means auto mode while this quirk is active,
+ * as this is far more likely than the ThinkPad being in level 7,
+ * which is only used by the firmware during thermal emergencies.
+ */
+
+static void fan_quirk1_detect(void)
+{
+ /* In some ThinkPads, neither the EC nor the ACPI
+ * DSDT initialize the HFSP register, and it ends up
+ * being initially set to 0x07 when it *could* be
+ * either 0x07 or 0x80.
+ *
+ * Enable for TP-1Y (T43), TP-78 (R51e),
+ * TP-76 (R52), TP-70 (T43, R52), which are known
+ * to be buggy. */
+ if (fan_control_initial_status == 0x07) {
+ switch (thinkpad_id.ec_model) {
+ case 0x5931: /* TP-1Y */
+ case 0x3837: /* TP-78 */
+ case 0x3637: /* TP-76 */
+ case 0x3037: /* TP-70 */
+ printk(TPACPI_NOTICE
+ "fan_init: initial fan status is unknown, "
+ "assuming it is in auto mode\n");
+ tp_features.fan_ctrl_status_undef = 1;
+ ;;
+ }
+ }
+}
+
+static void fan_quirk1_handle(u8 *fan_status)
+{
+ if (unlikely(tp_features.fan_ctrl_status_undef)) {
+ if (*fan_status != fan_control_initial_status) {
+ /* something changed the HFSP regisnter since
+ * driver init time, so it is not undefined
+ * anymore */
+ tp_features.fan_ctrl_status_undef = 0;
+ } else {
+ /* Return most likely status. In fact, it
+ * might be the only possible status */
+ *fan_status = TP_EC_FAN_AUTO;
+ }
+ }
+}
+