i8k: make fan multiplier tunable with a module parameter

The i8k driver multiplies the fan speed reported by the BIOS with a factor of
30.  On my Dell Latitude D800, this factor is not required.

I'd suggest to make this configurable.

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/char/i8k.c

@@ -77,6 +77,10 @@ static int power_status;
 module_param(power_status, bool, 0600);
 MODULE_PARM_DESC(power_status, "Report power status in /proc/i8k");
 
+static int fan_mult = I8K_FAN_MULT;
+module_param(fan_mult, int, 0);
+MODULE_PARM_DESC(fan_mult, "Factor to multiply fan speed with");
+
 static int i8k_open_fs(struct inode *inode, struct file *file);
 static int i8k_ioctl(struct inode *, struct file *, unsigned int,
 		     unsigned long);
@@ -239,7 +243,7 @@ static int i8k_get_fan_speed(int fan)
 	struct smm_regs regs = { .eax = I8K_SMM_GET_SPEED, };
 
 	regs.ebx = fan & 0xff;
-	return i8k_smm(&regs) ? : (regs.eax & 0xffff) * I8K_FAN_MULT;
+	return i8k_smm(&regs) ? : (regs.eax & 0xffff) * fan_mult;
 }
 
 /*