1 files changed, 48 insertions, 12 deletions

diff --git a/drivers/char/i8k.c b/drivers/char/i8k.c
index d6e8a267d3a6..6ad087240cef 100644
--- a/drivers/char/i8k.c
+++ b/drivers/char/i8k.c
@@ -6,6 +6,7 @@
  * Hwmon integration:
  * Copyright (C) 2011  Jean Delvare <jdelvare@suse.de>
  * Copyright (C) 2013, 2014  Guenter Roeck <linux@roeck-us.net>
+ * Copyright (C) 2014  Pali Rohár <pali.rohar@gmail.com>
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the
@@ -42,12 +43,14 @@
 #define I8K_SMM_SET_FAN         0x01a3
 #define I8K_SMM_GET_FAN         0x00a3
 #define I8K_SMM_GET_SPEED       0x02a3
+#define I8K_SMM_GET_NOM_SPEED   0x04a3
 #define I8K_SMM_GET_TEMP        0x10a3
 #define I8K_SMM_GET_TEMP_TYPE   0x11a3
 #define I8K_SMM_GET_DELL_SIG1   0xfea3
 #define I8K_SMM_GET_DELL_SIG2   0xffa3
 
 #define I8K_FAN_MULT            30
+#define I8K_FAN_MAX_RPM         30000
 #define I8K_MAX_TEMP            127
 
 #define I8K_FN_NONE             0x00
@@ -64,7 +67,7 @@ static DEFINE_MUTEX(i8k_mutex);
 static char bios_version[4];
 static struct device *i8k_hwmon_dev;
 static u32 i8k_hwmon_flags;
-static uint i8k_fan_mult;
+static uint i8k_fan_mult = I8K_FAN_MULT;
 static uint i8k_pwm_mult;
 static uint i8k_fan_max = I8K_FAN_HIGH;
 
@@ -95,13 +98,13 @@ static bool power_status;
 module_param(power_status, bool, 0600);
 MODULE_PARM_DESC(power_status, "Report power status in /proc/i8k");
 
-static uint fan_mult = I8K_FAN_MULT;
+static uint fan_mult;
 module_param(fan_mult, uint, 0);
-MODULE_PARM_DESC(fan_mult, "Factor to multiply fan speed with");
+MODULE_PARM_DESC(fan_mult, "Factor to multiply fan speed with (default: autodetect)");
 
-static uint fan_max = I8K_FAN_HIGH;
+static uint fan_max;
 module_param(fan_max, uint, 0);
-MODULE_PARM_DESC(fan_max, "Maximum configurable fan speed");
+MODULE_PARM_DESC(fan_max, "Maximum configurable fan speed (default: autodetect)");
 
 static int i8k_open_fs(struct inode *inode, struct file *file);
 static long i8k_ioctl(struct file *, unsigned int, unsigned long);
@@ -276,6 +279,17 @@ static int i8k_get_fan_speed(int fan)
 }
 
 /*
+ * Read the fan nominal rpm for specific fan speed.
+ */
+static int i8k_get_fan_nominal_speed(int fan, int speed)
+{
+        struct smm_regs regs = { .eax = I8K_SMM_GET_NOM_SPEED, };
+
+        regs.ebx = (fan & 0xff) | (speed << 8);
+        return i8k_smm(&regs) ? : (regs.eax & 0xffff) * i8k_fan_mult;
+}
+
+/*
  * Set the fan speed (off, low, high). Returns the new fan status.
  */
 static int i8k_set_fan(int fan, int speed)
@@ -863,6 +877,7 @@ MODULE_DEVICE_TABLE(dmi, i8k_dmi_table);
 static int __init i8k_probe(void)
 {
         const struct dmi_system_id *id;
+        int fan, ret;
 
         /*
          * Get DMI information
@@ -891,19 +906,40 @@ static int __init i8k_probe(void)
                         return -ENODEV;
         }
 
-        i8k_fan_mult = fan_mult;
-        i8k_fan_max = fan_max ? : I8K_FAN_HIGH; /* Must not be 0 */
+        /*
+         * Set fan multiplier and maximal fan speed from dmi config
+         * Values specified in module parameters override values from dmi
+         */
         id = dmi_first_match(i8k_dmi_table);
         if (id && id->driver_data) {
                 const struct i8k_config_data *conf = id->driver_data;
-
-                if (fan_mult == I8K_FAN_MULT && conf->fan_mult)
-                        i8k_fan_mult = conf->fan_mult;
-                if (fan_max == I8K_FAN_HIGH && conf->fan_max)
-                        i8k_fan_max = conf->fan_max;
+                if (!fan_mult && conf->fan_mult)
+                        fan_mult = conf->fan_mult;
+                if (!fan_max && conf->fan_max)
+                        fan_max = conf->fan_max;
         }
+
+        i8k_fan_max = fan_max ? : I8K_FAN_HIGH; /* Must not be 0 */
         i8k_pwm_mult = DIV_ROUND_UP(255, i8k_fan_max);
 
+        if (!fan_mult) {
+                /*
+                 * Autodetect fan multiplier based on nominal rpm
+                 * If fan reports rpm value too high then set multiplier to 1
+                 */
+                for (fan = 0; fan < 2; ++fan) {
+                        ret = i8k_get_fan_nominal_speed(fan, i8k_fan_max);
+                        if (ret < 0)
+                                continue;
+                        if (ret > I8K_FAN_MAX_RPM)
+                                i8k_fan_mult = 1;
+                        break;
+                }
+        } else {
+                /* Fan multiplier was specified in module param or in dmi */
+                i8k_fan_mult = fan_mult;
+        }
+
         return 0;
 }