drivers/char/i8k.c  |    4 ++++
 include/linux/i8k.h |   22 ++++++++++++++++------
 2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/drivers/char/i8k.c b/drivers/char/i8k.c
index 40cc0cf2ded6..e4b1613543ed 100644
--- a/drivers/char/i8k.c
+++ b/drivers/char/i8k.c
@@ -326,6 +326,10 @@ i8k_ioctl_unlocked(struct file *fp, unsigned int cmd, unsigned long arg)
 	if (!argp)
 		return -EINVAL;
 
+	/* We had some bad 64-bit confusion */
+	if ((arg >> _IOC_SIZESHIFT) & _IOC_SIZEMASK) == 8)
+		arg -= 4 << _IOC_SIZESHIFT;
+
 	switch (cmd) {
 	case I8K_BIOS_VERSION:
 		val = i8k_get_bios_version();
diff --git a/include/linux/i8k.h b/include/linux/i8k.h
index 1c45ba505115..650f4015c89c 100644
--- a/include/linux/i8k.h
+++ b/include/linux/i8k.h
@@ -20,14 +20,24 @@
 #define I8K_PROC		"/proc/i8k"
 #define I8K_PROC_FMT		"1.0"
 
+/*
+ * For hysterical raisins we expose the wrong size to user space
+ * in the ioctl numbering. The actual real data size is "int".
+ */
+#ifdef __KERNEL__
+#define borked_i8k_arg int
+#else
+#define borked_i8k_arg size_t
+#endif
+
 #define I8K_BIOS_VERSION	_IOR ('i', 0x80, int)	/* broken: meant 4 bytes */
 #define I8K_MACHINE_ID		_IOR ('i', 0x81, int)	/* broken: meant 16 bytes */
-#define I8K_POWER_STATUS	_IOR ('i', 0x82, size_t)
-#define I8K_FN_STATUS		_IOR ('i', 0x83, size_t)
-#define I8K_GET_TEMP		_IOR ('i', 0x84, size_t)
-#define I8K_GET_SPEED		_IOWR('i', 0x85, size_t)
-#define I8K_GET_FAN		_IOWR('i', 0x86, size_t)
-#define I8K_SET_FAN		_IOWR('i', 0x87, size_t)
+#define I8K_POWER_STATUS	_IOR ('i', 0x82, borked_i8k_arg)
+#define I8K_FN_STATUS		_IOR ('i', 0x83, borked_i8k_arg)
+#define I8K_GET_TEMP		_IOR ('i', 0x84, borked_i8k_arg)
+#define I8K_GET_SPEED		_IOWR('i', 0x85, borked_i8k_arg)
+#define I8K_GET_FAN		_IOWR('i', 0x86, borked_i8k_arg)
+#define I8K_SET_FAN		_IOWR('i', 0x87, borked_i8k_arg)
 
 #define I8K_FAN_LEFT		1
 #define I8K_FAN_RIGHT		0