Merge branch 'kms-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb

* 'kms-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb:
  kgdb,docs: Update the kgdb docs to include kms
  drm_fb_helper: Preserve capability to use atomic kms
  i915: when kgdb is active display compression should be off
  drm/i915: use new fb debug hooks
  drm: add KGDB/KDB support
  fb: add hooks to handle KDB enter/exit
  kgdboc: Add call backs to allow kernel mode switching
  vt,console,kdb: automatically set kdb LINES variable
  vt,console,kdb: implement atomic console enter/leave functions

include/linux/console.h

@@ -55,6 +55,16 @@ struct consw {
 	void	(*con_invert_region)(struct vc_data *, u16 *, int);
 	u16    *(*con_screen_pos)(struct vc_data *, int);
 	unsigned long (*con_getxy)(struct vc_data *, unsigned long, int *, int *);
+	/*
+	 * Prepare the console for the debugger.  This includes, but is not
+	 * limited to, unblanking the console, loading an appropriate
+	 * palette, and allowing debugger generated output.
+	 */
+	int	(*con_debug_enter)(struct vc_data *);
+	/*
+	 * Restore the console to its pre-debug state as closely as possible.
+	 */
+	int	(*con_debug_leave)(struct vc_data *);
 };
 
 extern const struct consw *conswitchp;
@@ -69,6 +79,9 @@ int register_con_driver(const struct consw *csw, int first, int last);
 int unregister_con_driver(const struct consw *csw);
 int take_over_console(const struct consw *sw, int first, int last, int deflt);
 void give_up_console(const struct consw *sw);
+int con_debug_enter(struct vc_data *vc);
+int con_debug_leave(void);
+
 /* scroll */
 #define SM_UP       (1)
 #define SM_DOWN     (2)

include/linux/fb.h

@@ -3,6 +3,9 @@
 
 #include <linux/types.h>
 #include <linux/i2c.h>
+#ifdef __KERNEL__
+#include <linux/kgdb.h>
+#endif /* __KERNEL__ */
 
 /* Definitions of frame buffers						*/
 
@@ -607,6 +610,12 @@ struct fb_deferred_io {
  * LOCKING NOTE: those functions must _ALL_ be called with the console
  * semaphore held, this is the only suitable locking mechanism we have
  * in 2.6. Some may be called at interrupt time at this point though.
+ *
+ * The exception to this is the debug related hooks.  Putting the fb
+ * into a debug state (e.g. flipping to the kernel console) and restoring
+ * it must be done in a lock-free manner, so low level drivers should
+ * keep track of the initial console (if applicable) and may need to
+ * perform direct, unlocked hardware writes in these hooks.
  */
 
 struct fb_ops {
@@ -676,6 +685,10 @@ struct fb_ops {
 
 	/* teardown any resources to do with this framebuffer */
 	void (*fb_destroy)(struct fb_info *info);
+
+	/* called at KDB enter and leave time to prepare the console */
+	int (*fb_debug_enter)(struct fb_info *info);
+	int (*fb_debug_leave)(struct fb_info *info);
 };
 
 #ifdef CONFIG_FB_TILEBLITTING

include/linux/kdb.h

@@ -114,4 +114,8 @@ enum {
 	KDB_INIT_EARLY,
 	KDB_INIT_FULL,
 };
+
+extern int kdbgetintenv(const char *, int *);
+extern int kdb_set(int, const char **);
+
 #endif	/* !_KDB_H */