Input: sparse-keymap - report KEY_UNKNOWN for unknown scan codes

This allows for debugging non-functional keys easily from
userspace.

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/input/sparse-keymap.c b/drivers/input/sparse-keymap.c
index 74bca5d2f6dc..fdb6a3976f94 100644
--- a/drivers/input/sparse-keymap.c
+++ b/drivers/input/sparse-keymap.c
@@ -209,6 +209,7 @@ int sparse_keymap_setup(struct input_dev *dev,
         }
 
         if (test_bit(EV_KEY, dev->evbit)) {
+                __set_bit(KEY_UNKNOWN, dev->keybit);
                 __set_bit(EV_MSC, dev->evbit);
                 __set_bit(MSC_SCAN, dev->mscbit);
         }
@@ -311,12 +312,19 @@ bool sparse_keymap_report_event(struct input_dev *dev, unsigned int code,
 {
         const struct key_entry *ke =
                 sparse_keymap_entry_from_scancode(dev, code);
+        struct key_entry unknown_ke;
 
         if (ke) {
                 sparse_keymap_report_entry(dev, ke, value, autorelease);
                 return true;
         }
 
+        /* Report an unknown key event as a debugging aid */
+        unknown_ke.type = KE_KEY;
+        unknown_ke.code = code;
+        unknown_ke.keycode = KEY_UNKNOWN;
+        sparse_keymap_report_entry(dev, &unknown_ke, value, true);
+
         return false;
 }
 EXPORT_SYMBOL(sparse_keymap_report_event);