2 files changed, 31 insertions, 1 deletions

diff --git a/drivers/misc/thinkpad_acpi.c b/drivers/misc/thinkpad_acpi.c
index c0a023cc5ded..7dc3a2206195 100644
--- a/drivers/misc/thinkpad_acpi.c
+++ b/drivers/misc/thinkpad_acpi.c
@@ -2935,6 +2935,9 @@ static ssize_t fan_fan_watchdog_store(struct device_driver *drv,
         if (parse_strtoul(buf, 120, &t))
                 return -EINVAL;
 
+        if (!fan_control_allowed)
+                return -EPERM;
+
         fan_watchdog_maxinterval = t;
         fan_watchdog_reset();
 
@@ -3046,6 +3049,14 @@ static int __init fan_init(struct ibm_init_struct *iibm)
                   fan_control_access_mode != TPACPI_FAN_WR_NONE),
                 fan_status_access_mode, fan_control_access_mode);
 
+        /* fan control master switch */
+        if (!fan_control_allowed) {
+                fan_control_access_mode = TPACPI_FAN_WR_NONE;
+                fan_control_commands = 0;
+                dbg_printk(TPACPI_DBG_INIT,
+                           "fan control features disabled by parameter\n");
+        }
+
         /* update fan_control_desired_level */
         if (fan_status_access_mode != TPACPI_FAN_NONE)
                 fan_get_status_safe(NULL);
@@ -3203,6 +3214,9 @@ static void fan_watchdog_reset(void)
 
 static int fan_set_level(int level)
 {
+        if (!fan_control_allowed)
+                return -EPERM;
+
         switch (fan_control_access_mode) {
         case TPACPI_FAN_WR_ACPI_SFAN:
                 if (level >= 0 && level <= 7) {
@@ -3242,6 +3256,9 @@ static int fan_set_level_safe(int level)
 {
         int rc;
 
+        if (!fan_control_allowed)
+                return -EPERM;
+
         rc = mutex_lock_interruptible(&fan_mutex);
         if (rc < 0)
                 return rc;
@@ -3262,6 +3279,9 @@ static int fan_set_enable(void)
         u8 s;
         int rc;
 
+        if (!fan_control_allowed)
+                return -EPERM;
+
         rc = mutex_lock_interruptible(&fan_mutex);
         if (rc < 0)
                 return rc;
@@ -3315,6 +3335,9 @@ static int fan_set_disable(void)
 {
         int rc;
 
+        if (!fan_control_allowed)
+                return -EPERM;
+
         rc = mutex_lock_interruptible(&fan_mutex);
         if (rc < 0)
                 return rc;
@@ -3351,6 +3374,9 @@ static int fan_set_speed(int speed)
 {
         int rc;
 
+        if (!fan_control_allowed)
+                return -EPERM;
+
         rc = mutex_lock_interruptible(&fan_mutex);
         if (rc < 0)
                 return rc;
@@ -3558,7 +3584,6 @@ static struct ibm_struct fan_driver_data = {
         .read = fan_read,
         .write = fan_write,
         .exit = fan_exit,
-        .flags.experimental = 1,
 };
 
 /****************************************************************************
@@ -3879,6 +3904,9 @@ module_param_named(debug, dbg_level, uint, 0);
 static int force_load;
 module_param(force_load, int, 0);
 
+static int fan_control_allowed;
+module_param_named(fan_control, fan_control_allowed, int, 0);
+
 #define IBM_PARAM(feature) \
         module_param_call(feature, set_ibm_param, NULL, NULL, 0)
 
diff --git a/drivers/misc/thinkpad_acpi.h b/drivers/misc/thinkpad_acpi.h
index 8348fc653009..a9e709368256 100644
--- a/drivers/misc/thinkpad_acpi.h
+++ b/drivers/misc/thinkpad_acpi.h
@@ -375,6 +375,8 @@ enum fan_control_commands {
                                                  * and also watchdog cmd */
 };
 
+static int fan_control_allowed;
+
 static enum fan_status_access_mode fan_status_access_mode;
 static enum fan_control_access_mode fan_control_access_mode;
 static enum fan_control_commands fan_control_commands;