From 3a4e9bd25caf9b75902b6a22122820518c3e5439 Mon Sep 17 00:00:00 2001
From: Andrew Kozlik <andrew.kozlik@gmail.com>
Date: Mon, 2 Dec 2019 12:04:34 +0100
Subject: [PATCH] core/ui: Ignore any new alert requests if an alert is already
 in progress in order to avoid multiple alerts overlapping.

---
 core/src/apps/webauthn/fido2.py |  2 +-
 core/src/trezor/ui/__init__.py  | 16 +++++++++++++++-
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/core/src/apps/webauthn/fido2.py b/core/src/apps/webauthn/fido2.py
index 1136945585..02ad16d475 100644
--- a/core/src/apps/webauthn/fido2.py
+++ b/core/src/apps/webauthn/fido2.py
@@ -1027,7 +1027,7 @@ def dispatch_cmd(req: Cmd, dialog_mgr: DialogManager) -> Optional[Cmd]:
     elif req.cmd == _CMD_WINK:
         if __debug__:
             log.debug(__name__, "_CMD_WINK")
-        loop.schedule(ui.alert())
+        ui.alert()
         return req
     elif req.cmd == _CMD_CBOR and _ALLOW_FIDO2:
         if not req.data:
diff --git a/core/src/trezor/ui/__init__.py b/core/src/trezor/ui/__init__.py
index e6b1ae990e..1b1ee3a389 100644
--- a/core/src/trezor/ui/__init__.py
+++ b/core/src/trezor/ui/__init__.py
@@ -34,6 +34,9 @@ VIEWY = const(9)
 # channel used to cancel layouts, see `Cancelled` exception
 layout_chan = loop.chan()
 
+# allow only one alert at a time to avoid alerts overlapping
+_alert_in_progress = False
+
 # in debug mode, display an indicator in top right corner
 if __debug__:
 
@@ -78,7 +81,7 @@ def pulse(period: int, offset: int = 0) -> float:
     return 0.5 + 0.5 * math.sin(2 * math.pi * (utime.ticks_us() + offset) / period)
 
 
-async def alert(count: int = 3) -> None:
+async def _alert(count: int) -> None:
     short_sleep = loop.sleep(20000)
     long_sleep = loop.sleep(80000)
     for i in range(count * 2):
@@ -89,6 +92,17 @@ async def alert(count: int = 3) -> None:
             display.backlight(style.BACKLIGHT_DIM)
             await long_sleep
     display.backlight(style.BACKLIGHT_NORMAL)
+    global _alert_in_progress
+    _alert_in_progress = False
+
+
+def alert(count: int = 3) -> None:
+    global _alert_in_progress
+    if _alert_in_progress:
+        return
+
+    _alert_in_progress = True
+    loop.schedule(_alert(count))
 
 
 async def click() -> Pos: