fix(core): remove premature backlight fade-in after device wakeup
What the developer wrote
Authored by tychovrahe
fix(core): remove premature backlight fade-in after device wakeup
[no changelog]
What changed, and why it matters
This commit removes a single line that automatically brightened the screen when a Trezor device woke up from suspend. The change is described as fixing a 'premature' backlight fade-in. There is no direct evidence in the commit that this is a security fix; it appears to be a user-experience or visual polish change. The security relevance, if any, would be minor: a brief screen illumination could theoretically reveal that the device had woken up or what screen was displayed, but no sensitive data or controls are exposed.
Treat as a low-risk UX fix unless additional vendor guidance or a security advisory is published. No immediate user action is required. If reviewing for security, confirm that the intended post-wakeup backlight state does not leave the screen unexpectedly illuminated in a way that could leak screen contents to a nearby observer.
Security signals we found
Change touches device wakeup/resume behavior
Backlight behavior can affect shoulder-surfing or information-leakage risk in constrained physical environments
No security keywords, CVE, advisory, or changelog entry present in commit
Evidence from the diff
The patch deletes backlight_fade(BacklightLevels.NORMAL) from the lock_manager.py resume path. Previously, when the device resumed from suspend, it would immediately fade the backlight to normal brightness after setting the homescreen. The commit removes this automatic fade, likely so the backlight remains off or follows another policy until an explicit action turns it on. The diff is one deletion in a UI/flow file with no changelog entry and no security framing.
Changed components
core/src/apps/common/lock_manager.pyTrezor Core suspend/resume UI flowInspect captured patch +0 / −1
diff --git a/core/src/apps/common/lock_manager.py b/core/src/apps/common/lock_manager.py
index bc8e604e5..3d6c97290 100644
--- a/core/src/apps/common/lock_manager.py
+++ b/core/src/apps/common/lock_manager.py
@@ -87,7 +87,6 @@ else:
_SHOULD_SUSPEND = False
set_homescreen()
- backlight_fade(BacklightLevels.NORMAL)
async def _suspend_and_resume_task() -> None:
"""Task to suspend Trezor and handle wakeup.
Why this scored 17/100
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