kgdboc: reset input devices (keyboards) when exiting debugger

Use the newly exported input_reset_device() call to reset LED state and
mark all keys/buttons as released on all keyboard-like devices when
exiting the debugger.

[jason.wessel@windriver.com: fix compile without keyboard input driver]
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 59 insertions, 0 deletions

diff --git a/drivers/serial/kgdboc.c b/drivers/serial/kgdboc.c
index d4b711c9a416..3374618300af 100644
--- a/drivers/serial/kgdboc.c
+++ b/drivers/serial/kgdboc.c
@@ -18,6 +18,7 @@
 #include <linux/tty.h>
 #include <linux/console.h>
 #include <linux/vt_kern.h>
+#include <linux/input.h>
 
 #define MAX_CONFIG_LEN          40
 
@@ -37,6 +38,61 @@ static struct tty_driver	*kgdb_tty_driver;
 static int                      kgdb_tty_line;
 
 #ifdef CONFIG_KDB_KEYBOARD
+static int kgdboc_reset_connect(struct input_handler *handler,
+                                struct input_dev *dev,
+                                const struct input_device_id *id)
+{
+        input_reset_device(dev);
+
+        /* Retrun an error - we do not want to bind, just to reset */
+        return -ENODEV;
+}
+
+static void kgdboc_reset_disconnect(struct input_handle *handle)
+{
+        /* We do not expect anyone to actually bind to us */
+        BUG();
+}
+
+static const struct input_device_id kgdboc_reset_ids[] = {
+        {
+                .flags = INPUT_DEVICE_ID_MATCH_EVBIT,
+                .evbit = { BIT_MASK(EV_KEY) },
+        },
+        { }
+};
+
+static struct input_handler kgdboc_reset_handler = {
+        .connect        = kgdboc_reset_connect,
+        .disconnect     = kgdboc_reset_disconnect,
+        .name           = "kgdboc_reset",
+        .id_table       = kgdboc_reset_ids,
+};
+
+static DEFINE_MUTEX(kgdboc_reset_mutex);
+
+static void kgdboc_restore_input_helper(struct work_struct *dummy)
+{
+        /*
+         * We need to take a mutex to prevent several instances of
+         * this work running on different CPUs so they don't try
+         * to register again already registered handler.
+         */
+        mutex_lock(&kgdboc_reset_mutex);
+
+        if (input_register_handler(&kgdboc_reset_handler) == 0)
+                input_unregister_handler(&kgdboc_reset_handler);
+
+        mutex_unlock(&kgdboc_reset_mutex);
+}
+
+static DECLARE_WORK(kgdboc_restore_input_work, kgdboc_restore_input_helper);
+
+static void kgdboc_restore_input(void)
+{
+        schedule_work(&kgdboc_restore_input_work);
+}
+
 static int kgdboc_register_kbd(char **cptr)
 {
         if (strncmp(*cptr, "kbd", 3) == 0) {
@@ -64,10 +120,12 @@ static void kgdboc_unregister_kbd(void)
                         i--;
                 }
         }
+        flush_work_sync(&kgdboc_restore_input_work);
 }
 #else /* ! CONFIG_KDB_KEYBOARD */
 #define kgdboc_register_kbd(x) 0
 #define kgdboc_unregister_kbd()
+#define kgdboc_restore_input()
 #endif /* ! CONFIG_KDB_KEYBOARD */
 
 static int kgdboc_option_setup(char *opt)
@@ -231,6 +289,7 @@ static void kgdboc_post_exp_handler(void)
                 dbg_restore_graphics = 0;
                 con_debug_leave();
         }
+        kgdboc_restore_input();
 }
 
 static struct kgdb_io kgdboc_io_ops = {