[PATCH] therm_adt746x: gradually change fan speed and start both fans on Albooks

Here's the patch that supercedes the one I asked you to drop.  It changes
the fan speed logic so that the fans will go incrementally fast instead of
using just two steps.  Also, it starts and stops both fans instead of just
one on Powerbooks 15" and 17" (functionality asked by most of the Albooks
users on Debian's ML, and justified by the fact that fan 1 and fan 2 do not
correspond to CPU and GPU, as we previously thought).
Signed-off-by: Colin Leroy <colin@colino.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/macintosh/therm_adt746x.c

@@ -61,8 +61,8 @@ MODULE_PARM_DESC(limit_adjust,"Adjust maximum temperatures (50 cpu, 70 gpu) "
 		 "by N degrees.");
 
 MODULE_PARM(fan_speed,"i");
-MODULE_PARM_DESC(fan_speed,"Specify fan speed (0-255) when lim < temp < lim+8 "
-		 "(default 128)");
+MODULE_PARM_DESC(fan_speed,"Specify starting fan speed (0-255) "
+		 "(default 64)");
 
 struct thermostat {
 	struct i2c_client	clt;
@@ -71,7 +71,7 @@ struct thermostat {
 	u8			initial_limits[3];
 	u8			limits[3];
 	int			last_speed[2];
-	int			overriding[2];
+	int			last_var[2];
 };
 
 static enum {ADT7460, ADT7467} therm_type;
@@ -211,10 +211,10 @@ static void write_fan_speed(struct thermostat *th, int speed, int fan)
 	
 	if (th->last_speed[fan] != speed) {
 		if (speed == -1)
-			printk(KERN_INFO "adt746x: Setting speed to automatic "
+			printk(KERN_DEBUG "adt746x: Setting speed to automatic "
 				"for %s fan.\n", fan?"GPU":"CPU");
 		else
-			printk(KERN_INFO "adt746x: Setting speed to %d "
+			printk(KERN_DEBUG "adt746x: Setting speed to %d "
 				"for %s fan.\n", speed, fan?"GPU":"CPU");
 	} else
 		return;
@@ -278,43 +278,46 @@ static void update_fans_speed (struct thermostat *th)
 		int started = 0;
 		int fan_number = (therm_type == ADT7460 && i == 2);
 		int var = th->temps[i] - th->limits[i];
-		if (var > 8) {
-			if (th->overriding[fan_number] == 0)
-				printk(KERN_INFO "adt746x: Limit exceeded by "
-					"%d, overriding specified fan speed "
-					"for %s.\n", var,
-					fan_number?"GPU":"CPU");
-
-			th->overriding[fan_number] = 1;
-			write_fan_speed(th, 255, fan_number);
-			started = 1;
-		} else if ((!th->overriding[fan_number] || var < 6) && var > 0) {
-			if (th->overriding[fan_number] == 1)
-				printk(KERN_INFO "adt746x: Limit exceeded by "
-					"%d, setting speed to specified "
-					"for %s.\n", var,
-					fan_number?"GPU":"CPU");
-
-			th->overriding[fan_number] = 0;
-			write_fan_speed(th, fan_speed, fan_number);
+
+		if (var > -1) {
+			int step = (255 - fan_speed) / 7;
+			int new_speed = 0;
+
+			/* hysteresis : change fan speed only if variation is
+			 * more than two degrees */
+			if (abs(var - th->last_var[fan_number]) < 2)
+				continue;
+
 			started = 1;
-		} else if (var < -1) {
-			/* don't stop iBook fan if GPU is cold and CPU is not
+			new_speed = fan_speed + ((var-1)*step);
+
+			if (new_speed < fan_speed)
+				new_speed = fan_speed;
+			if (new_speed > 255)
+				new_speed = 255;
+
+			printk(KERN_DEBUG "adt746x: setting fans speed to %d "
+					 "(limit exceeded by %d on %s) \n",
+					new_speed, var,
+					fan_number?"GPU/pwr":"CPU");
+			write_both_fan_speed(th, new_speed);
+			th->last_var[fan_number] = var;
+		} else if (var < -2) {
+			/* don't stop fan if GPU/power is cold and CPU is not
 			 * so cold (lastvar >= -1) */
-			if (therm_type == ADT7460 || lastvar < -1 || i == 1) {
+			if (i == 2 && lastvar < -1) {
 				if (th->last_speed[fan_number] != 0)
-					printk(KERN_INFO "adt746x: Stopping %s "
-						"fan.\n",
-						fan_number?"GPU":"CPU");
-				write_fan_speed(th, 0, fan_number);
+					printk(KERN_DEBUG "adt746x: Stopping "
+						"fans.\n");
+				write_both_fan_speed(th, 0);
 			}
 		}
 
 		lastvar = var;
 
-		if (started && therm_type == ADT7467)
+		if (started)
 			return; /* we don't want to re-stop the fan
-				* if CPU is heating and GPU is not */
+				* if CPU is heating and GPU/power is not */
 	}
 }
 
@@ -391,7 +394,7 @@ static int attach_one_thermostat(struct i2c_adapter *adapter, int addr,
 
 	/* force manual control to start the fan quieter */
 	if (fan_speed == -1)
-		fan_speed=128;
+		fan_speed = 64;
 	
 	if(therm_type == ADT7460) {
 		printk(KERN_INFO "adt746x: ADT7460 initializing\n");
@@ -424,7 +427,9 @@ static int attach_one_thermostat(struct i2c_adapter *adapter, int addr,
 	/* be sure to really write fan speed the first time */
 	th->last_speed[0] = -2;
 	th->last_speed[1] = -2;
-	
+	th->last_var[0] = -80;
+	th->last_var[1] = -80;
+
 	if (fan_speed != -1) {
 		/* manual mode, stop fans */
 		write_both_fan_speed(th, 0);