kgdboc: Add call backs to allow kernel mode switching

Add the kms keyword processing to kgdboc and the callbacks to invoke
console switching when ever kgdboc is started with "kgdboc=kms,kbd".

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 18 insertions, 0 deletions

diff --git a/drivers/serial/kgdboc.c b/drivers/serial/kgdboc.c
index a9a94ae72349..39f9a1adaa75 100644
--- a/drivers/serial/kgdboc.c
+++ b/drivers/serial/kgdboc.c
@@ -17,6 +17,7 @@
 #include <linux/kdb.h>
 #include <linux/tty.h>
 #include <linux/console.h>
+#include <linux/vt_kern.h>
 
 #define MAX_CONFIG_LEN          40
 
@@ -31,6 +32,7 @@ static struct kparam_string kps = {
         .maxlen                 = MAX_CONFIG_LEN,
 };
 
+static int kgdboc_use_kms;  /* 1 if we use kernel mode switching */
 static struct tty_driver        *kgdb_tty_driver;
 static int                      kgdb_tty_line;
 
@@ -104,6 +106,12 @@ static int configure_kgdboc(void)
         kgdboc_io_ops.is_console = 0;
         kgdb_tty_driver = NULL;
 
+        kgdboc_use_kms = 0;
+        if (strncmp(cptr, "kms,", 4) == 0) {
+                cptr += 4;
+                kgdboc_use_kms = 1;
+        }
+
         if (kgdboc_register_kbd(&cptr))
                 goto do_register;
 
@@ -201,8 +209,14 @@ static int param_set_kgdboc_var(const char *kmessage, struct kernel_param *kp)
         return configure_kgdboc();
 }
 
+static int dbg_restore_graphics;
+
 static void kgdboc_pre_exp_handler(void)
 {
+        if (!dbg_restore_graphics && kgdboc_use_kms) {
+                dbg_restore_graphics = 1;
+                con_debug_enter(vc_cons[fg_console].d);
+        }
         /* Increment the module count when the debugger is active */
         if (!kgdb_connected)
                 try_module_get(THIS_MODULE);
@@ -213,6 +227,10 @@ static void kgdboc_post_exp_handler(void)
         /* decrement the module count when the debugger detaches */
         if (!kgdb_connected)
                 module_put(THIS_MODULE);
+        if (kgdboc_use_kms && dbg_restore_graphics) {
+                dbg_restore_graphics = 0;
+                con_debug_leave();
+        }
 }
 
 static struct kgdb_io kgdboc_io_ops = {