diff --git a/CHANGES b/CHANGES
index d1da8502..28c8aa5f 100644
--- a/CHANGES
+++ b/CHANGES
@@ -11,6 +11,8 @@ SVN-HEAD
   Module eeprom: Hide Sony Vaio serial numbers to regular users (2.6 backport)
                  Drop useless debugging log messages
                  Recognize VGN as a valid Sony Vaio name prefix (2.6 backport)
+  Module gl518sm: Fix fan speed reading (2.6 backport)
+  Module gl520sm: Fix fan speed reading (2.6 backport)
   Program decode-dimms.pl: Fix DDR2 SDRAM module speed decoding
                            Update manufacturer IDs.
   Program decode-vaio.pl: Private data might not be readable by non-root users
diff --git a/kernel/chips/gl518sm.c b/kernel/chips/gl518sm.c
index a514a59d..996c17b6 100644
--- a/kernel/chips/gl518sm.c
+++ b/kernel/chips/gl518sm.c
@@ -85,12 +85,12 @@ static inline u8 FAN_TO_REG(long rpm, int div)
 	if (rpm == 0)
 		return 255;
 	rpm = SENSORS_LIMIT(rpm, 1, 1000000);
-	return SENSORS_LIMIT((960000 + rpm * div / 2) / (rpm * div), 1,
+	return SENSORS_LIMIT((480000 + rpm * div / 2) / (rpm * div), 1,
 			     254);
 }
 
 #define FAN_FROM_REG(val,div) \
- ( (val)==0 ? 0 : (val)==255 ? 0 : (960000/((val)*(div))) )
+ ( (val)==0 ? 0 : (val)==255 ? 0 : (480000/((val)*(div))) )
 
 #define IN_TO_REG(val) (SENSORS_LIMIT((((val)*10+8)/19),0,255))
 #define IN_FROM_REG(val) (((val)*19)/10)
diff --git a/kernel/chips/gl520sm.c b/kernel/chips/gl520sm.c
index 38ae7862..565ef66c 100644
--- a/kernel/chips/gl520sm.c
+++ b/kernel/chips/gl520sm.c
@@ -87,12 +87,12 @@ static inline u8 FAN_TO_REG(long rpm, int div)
 	if (rpm == 0)
 		return 255;
 	rpm = SENSORS_LIMIT(rpm, 1, 1000000);
-	return SENSORS_LIMIT((960000 + rpm * div / 2) / (rpm * div), 1,
+	return SENSORS_LIMIT((480000 + rpm * div / 2) / (rpm * div), 1,
 			     254);
 }
 
 #define FAN_FROM_REG(val,div) \
- ( (val)==0 ? 0 : (val)==255 ? 0 : (960000/((val)*(div))) )
+ ( (val)==0 ? 0 : (val)==255 ? 0 : (480000/((val)*(div))) )
 
 #define IN_TO_REG(val) (SENSORS_LIMIT((((val)*10+8)/19),0,255))
 #define IN_FROM_REG(val) (((val)*19)/10)