fix(core): properly respond to USB events while on a paginated screen

core/.changelog.d/1708.fixed

@@ -0,0 +1 @@
+Properly respond to USB events while on a paginated screen.

core/src/trezor/ui/components/tt/scroll.py

@@ -114,7 +114,7 @@ class Paginated(ui.Layout):
         await ctx.call(ButtonRequest(code=code, pages=len(self.pages)), ButtonAck)
         result = WAS_PAGED
         while result is WAS_PAGED:
-            result = await self
+            result = await ctx.wait(self)
 
         return result
 

tests/device_tests/test_cancel.py

@@ -67,3 +67,27 @@ def test_cancel_message_via_initialize(client, message):
     resp = client._raw_read()
 
     assert isinstance(resp, m.Features)
+
+
+@pytest.mark.skip_t1
+def test_cancel_on_paginated(client):
+    """Check that device is responsive on paginated screen. See #1708."""
+    # In #1708, the device would ignore USB (or UDP) events while waiting for the user
+    # to page through the screen. This means that this testcase, instead of failing,
+    # would get stuck waiting for the _raw_read result.
+    # I'm not spending the effort to modify the testcase to cause a _failure_ if that
+    # happens again. Just be advised that this should not get stuck.
+    message = m.SignMessage(
+        message=b"hello" * 64,
+        address_n=TEST_ADDRESS_N,
+        coin_name="Testnet",
+    )
+    resp = client.call_raw(message)
+    assert isinstance(resp, m.ButtonRequest)
+    assert resp.pages is not None
+    client._raw_write(m.ButtonAck())
+
+    client._raw_write(m.Cancel())
+    resp = client._raw_read()
+    assert isinstance(resp, m.Failure)
+    assert resp.code == m.FailureType.ActionCancelled

tests/ui_tests/fixtures.json

@@ -128,6 +128,7 @@
 "test_cancel.py::test_cancel_message_via_cancel[message1]": "83a76ca8054759209fc06244ee303f95e20da9e6ccdfe268d16fba5e0065de69",
 "test_cancel.py::test_cancel_message_via_initialize[message0]": "83a76ca8054759209fc06244ee303f95e20da9e6ccdfe268d16fba5e0065de69",
 "test_cancel.py::test_cancel_message_via_initialize[message1]": "83a76ca8054759209fc06244ee303f95e20da9e6ccdfe268d16fba5e0065de69",
+"test_cancel.py::test_cancel_on_paginated": "83a76ca8054759209fc06244ee303f95e20da9e6ccdfe268d16fba5e0065de69",
 "test_debuglink.py::test_softlock_instability": "bdc28bcdb709f6ffd74ba89bc34ff87a2516c9277bad701c1c6d9e9926ce6871",
 "test_descriptors.py::test_descriptors[Bitcoin-0-InputScriptType.SPENDADDRESS-descriptors0]": "2cfe6b7b4d74644c8bdef3f18d8a9be8c20787ab5e9af2588bac2c426a5f1da7",
 "test_descriptors.py::test_descriptors[Bitcoin-0-InputScriptType.SPENDP2SHWITNESS-descriptors4]": "5b87cbe3b60327d699545bf61101cf633f66d66bc485d692c51505c18519948a",