[RFC PATCH 4/5] kgdboc: reset input devices (keyboards) when exiting debugger

Jason Wessel
2010-11-05T19:05:42Z

From: Dmitry Torokhov <dtor@mail.ru>

Allow all keys to be released when resuming kernel execution to avoid
problems with auto repeated keystrokes and the need to press a key an
extra time to reset its state.

[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>
---
drivers/serial/kgdboc.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 59 insertions(+), 0 deletions(-)

diff --git a/drivers/serial/kgdboc.c b/drivers/serial/kgdboc.c
index d4b711c..3374618 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 = {
--
1.6.3.3