diff --git a/drivers/misc/thinkpad_acpi.c b/drivers/misc/thinkpad_acpi.c
index 81693b4c23b861a0b51947a8e58036f6c26eaf45..37891a8c030a229cb18deba84038f4c55af966d7 100644
--- a/drivers/misc/thinkpad_acpi.c
+++ b/drivers/misc/thinkpad_acpi.c
@@ -709,6 +709,8 @@ static int parse_strtoul(const char *buf,
 {
 	char *endp;
 
+	while (*buf && isspace(*buf))
+		buf++;
 	*value = simple_strtoul(buf, &endp, 0);
 	while (*endp && isspace(*endp))
 		endp++;