[PATCH] fbdev: Fix crash if fb_set_var() called before register_framebuffer()

["Antonino A. Daplas" <adaplas@hotpop.com>]

The field info->modelist is initialized during register_framebuffer.  This
field is also referred to in fb_set_var().  Thus a call to fb_set_var()
before register_framebuffer() will cause a crash.  A few drivers do this,
notably controlfb.  (This might fix reports of controlfb crashing in
powermacs).

Signed-off-by: Antonino Daplas <adaplas@pol.net>
---

 fbmem.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletion(-)

diff -Nru a/drivers/video/fbmem.c b/drivers/video/fbmem.c
--- a/drivers/video/fbmem.c	2004-11-23 21:20:13 +08:00
+++ b/drivers/video/fbmem.c	2004-11-25 01:09:22 +08:00
@@ -725,7 +725,10 @@
 			fb_set_cmap(&info->cmap, info);
 
 			fb_var_to_videomode(&mode, &info->var);
-			fb_add_videomode(&mode, &info->modelist);
+
+			if (info->modelist.prev && info->modelist.next &&
+			    !list_empty(&info->modelist))
+				fb_add_videomode(&mode, &info->modelist);
 
 			if (info->flags & FBINFO_MISC_MODECHANGEUSER) {
 				struct fb_event event;