Input: adbhid - fix capslock key state after suspend

If the adbhid module parameter restore_capslock_events is used,
sometimes capslock will get stuck down after resuming.

My fix is to remember the capslock state before suspend and then
ignore the first 'caps lock key down' message after resume if the
capslock LED was on before suspending.

Signed-off-by: Rodney Lorrimar <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/macintosh/adbhid.c

···
 	int flags;
 };
 
-#define FLAG_FN_KEY_PRESSED	0x00000001
-#define FLAG_POWER_FROM_FN	0x00000002
-#define FLAG_EMU_FWDEL_DOWN	0x00000004
-#define FLAG_CAPSLOCK_TRANSLATE	0x00000008
-#define FLAG_CAPSLOCK_DOWN	0x00000010
+#define FLAG_FN_KEY_PRESSED		0x00000001
+#define FLAG_POWER_FROM_FN		0x00000002
+#define FLAG_EMU_FWDEL_DOWN		0x00000004
+#define FLAG_CAPSLOCK_TRANSLATE		0x00000008
+#define FLAG_CAPSLOCK_DOWN		0x00000010
+#define FLAG_CAPSLOCK_IGNORE_NEXT	0x00000020
 
 static struct adbhid *adbhid[16];
 
···
 		if (keycode == ADB_KEY_CAPSLOCK && !up_flag) {
 			/* Key pressed, turning on the CapsLock LED.
 			 * The next 0xff will be interpreted as a release. */
-			ahid->flags |= FLAG_CAPSLOCK_TRANSLATE
+			if (ahid->flags & FLAG_CAPSLOCK_IGNORE_NEXT) {
+				/* Throw away this key event if it happens
+				 * just after resume. */
+				ahid->flags &= ~FLAG_CAPSLOCK_IGNORE_NEXT;
+				return;
+			} else {
+				ahid->flags |= FLAG_CAPSLOCK_TRANSLATE
 					| FLAG_CAPSLOCK_DOWN;
+			}
 		} else if (scancode == 0xff) {
 			/* Scancode 0xff usually signifies that the capslock
 			 * key was either pressed or released. */
···
 	return -1;
 }
 
+static void
+adbhid_kbd_capslock_remember(void)
+{
+	struct adbhid *ahid;
+	int i;
+
+	for (i = 1; i < 16; i++) {
+		ahid = adbhid[i];
+
+		if (ahid && ahid->id == ADB_KEYBOARD)
+			if (ahid->flags & FLAG_CAPSLOCK_TRANSLATE)
+				ahid->flags |= FLAG_CAPSLOCK_IGNORE_NEXT;
+	}
+}
+
 static int
 adb_message_handler(struct notifier_block *this, unsigned long code, void *x)
 {
···
 		}
 
 		/* Stop pending led requests */
-		while(leds_req_pending)
+		while (leds_req_pending)
 			adb_poll();
+
+		/* After resume, and if the capslock LED is on, the PMU will
+		 * send a "capslock down" key event. This confuses the
+		 * restore_capslock_events logic. Remember if the capslock
+		 * LED was on before suspend so the unwanted key event can
+		 * be ignored after resume. */
+		if (restore_capslock_events)
+			adbhid_kbd_capslock_remember();
+
 		break;
 
 	case ADB_MSG_POST_RESET: