feat(core): fade backlight even in case a background process is still running
What the developer wrote
Authored by matejcik
feat(core): fade backlight even in case a background process is still running
when autolock_interrupts_workflow is False and we need to wait for e.g.
transaction signing to finish before we can go to suspend
What changed, and why it matters
This small change moves where the screen backlight fade happens in the Trezor hardware wallet's lock/suspend logic. Previously, the screen dimmed only inside the suspend function. Now it also dims earlier when the device decides it should suspend but is still waiting for a background task (like signing a transaction) to finish. The goal is to avoid leaving the screen bright while the user is waiting for a long operation before the device can lock. This is a user-experience and minor privacy improvement, not a fix for a serious security flaw.
Treat as a routine firmware improvement. No urgent action required. Review whether the earlier fade could affect user confirmation prompts during long-running workflows, since fading the backlight before suspend might make the screen hard to read while a background operation is still active and the device is not yet suspended.
Security signals we found
Information disclosure reduction: screen content is hidden sooner when the device is unattended during long background operations
UI/UX timing change in autolock flow
No cryptographic, authorization, or memory-safety changes
Evidence from the diff
In core/src/apps/common/lock_manager.py, the import of BacklightLevels and backlight_fade is moved from inside suspend() to the module level, and backlight_fade(BacklightLevels.NONE) is added at the start of lock_device(). This ensures the display fades immediately when the autolock decision is made, even when autolock_interrupts_workflow is False and the device must wait for a background workflow (e.g., transaction signing) to complete before entering suspend_device(). The change reduces the window during which the screen remains lit after the lock interval expires.
Changed components
core/src/apps/common/lock_manager.pyTrezor Safe firmware autolock/suspend behaviorInspect captured patch +2 / −1
diff --git a/core/src/apps/common/lock_manager.py b/core/src/apps/common/lock_manager.py
index b12357f4..ed660b93 100644
--- a/core/src/apps/common/lock_manager.py
+++ b/core/src/apps/common/lock_manager.py
@@ -10,6 +10,7 @@ if utils.USE_POWER_MANAGER:
from trezor import io
from trezor.power_management.autodim import autodim_display
from trezor.power_management.suspend import suspend_device
+ from trezorui_api import BacklightLevels, backlight_fade
if TYPE_CHECKING:
from trezor import protobuf
@@ -37,6 +38,7 @@ else:
"""
global _SHOULD_SUSPEND
+ backlight_fade(BacklightLevels.NONE)
_SHOULD_SUSPEND = True
set_homescreen()
@@ -59,7 +61,6 @@ else:
The function will only return after Trezor has woken up.
"""
from trezor.ui import CURRENT_LAYOUT
- from trezorui_api import BacklightLevels, backlight_fade
global _SHOULD_SUSPEND
Why this scored 23/100
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