[PATCH] cfag12864b: fix crash when built-in and no parport present
The problem comes when ks0108/cfag12864b are built-in and no parallel port is
present. ks0108_init() is called first, as it should be, but fails to load
(as there is no parallel port to use).
After that, cfag12864b_init() gets called, without knowing anything about
ks0108 failed, and calls ks0108_writecontrol(), which dereferences an
uninitialized pointer.
Init order is OK, I think. The problem is how to stop cfag12864b_init() being
called if ks0108 failed to load. modprobe does it for us, but, how when
built-in?
Signed-off-by: Miguel Ojeda Sandonis <maxextreme@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/ks0108.h b/include/linux/ks0108.h
index 8047d4b..a2c54ac 100644
--- a/include/linux/ks0108.h
+++ b/include/linux/ks0108.h
@@ -43,4 +43,7 @@
/* Set the controller's current page (0..7) */
extern void ks0108_page(unsigned char page);
+/* Is the module inited? */
+extern unsigned char ks0108_isinited(void);
+
#endif /* _KS0108_H_ */