fbcon: allow fbcon to use the primary display driver

Allow fbcon to select the primary display adapter using the
fb_is_primary_device() arch-specific helper.  If a a primary adapter is
detected, fbcon will unbind the old adapter from the VT layer, then rebind
using the new adapter.  This requires that bind_/unbind_con_driver() be made
public.

Because this feature may produce unexpected behavior (from the user's POV),
this must be explicitly enabled in Kconfig.

[akpm@linux-foundation.org: export unbind_con_driver]
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/vt_kern.h b/include/linux/vt_kern.h
index d961635d0e61..0d034d89ee8a 100644
--- a/include/linux/vt_kern.h
+++ b/include/linux/vt_kern.h
@@ -75,6 +75,10 @@ int con_copy_unimap(struct vc_data *dst_vc, struct vc_data *src_vc);
 int vt_waitactive(int vt);
 void change_console(struct vc_data *new_vc);
 void reset_vc(struct vc_data *vc);
+extern int bind_con_driver(const struct consw *csw, int first, int last,
+                           int deflt);
+extern int unbind_con_driver(const struct consw *csw, int first, int last,
+                             int deflt);
 
 /*
  * vc_screen.c shares this temporary buffer with the console write code so that