drm: add KGDB/KDB support

Implement the callbacks for KDB entry/exit via the drm helpers.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
index f0a6afc..f22e7fe 100644
--- a/include/drm/drm_fb_helper.h
+++ b/include/drm/drm_fb_helper.h
@@ -32,6 +32,8 @@
 
 struct drm_fb_helper;
 
+#include <linux/kgdb.h>
+
 struct drm_fb_helper_crtc {
 	uint32_t crtc_id;
 	struct drm_mode_set mode_set;
@@ -78,6 +80,7 @@
 
 struct drm_fb_helper {
 	struct drm_framebuffer *fb;
+	struct drm_framebuffer *saved_fb;
 	struct drm_device *dev;
 	struct drm_display_mode *mode;
 	int crtc_count;
@@ -126,5 +129,7 @@
 bool drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper);
 bool drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper, int bpp_sel);
 int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper);
+int drm_fb_helper_debug_enter(struct fb_info *info);
+int drm_fb_helper_debug_leave(struct fb_info *info);
 
 #endif