Introduces non-blocking refresh capability with displayBufferAsync() that starts panel waveform and returns immediately, plus waitRefreshComplete() to block until refresh finishes. Panels without async support fall back to blocking refresh. Requires framebuffer to remain untouched during refresh and differential baseline rebuild before next update.
1. X3 wb_gc passive byte (the one-byte 0x54 to 0x00, matching stock's passive WB table in the gc nudge bank) Every X3 grayscale render, reader AA, covers, and the sleep-cover nudge, gets it. 2. X4 blotchy grays on sleep covers: the displayGrayscaleBase(HALF_REFRESH) revert (the gray nudge LUT being calibrated against the HALF pixel state, not FULL's)
Changes all sleep screen display refreshes from FULL_REFRESH to HALF_REFRESH to match OEM firmware behavior. The stock firmware uses a single-pass 0xD7 waveform for sleep screens, not the multi-flash GC waveform (0xF7) that FULL_REFRESH triggers. For grayscale mode, HALF_REFRESH is required because the gray nudge LUT is calibrated against the pixel charge state left by the single-pass waveform; using FULL_REFRESH causes blotchy noise in gray areas.
## Summary
* **What is the goal of this PR?** Fixes#2402. On the X3, the "Time to
Sleep"
picker's 5-minute side buttons were inverted (left increased, right
decreased)
and the on-screen legend didn't match the physical buttons.
* **What changes are included?**
* Flip the large-step (±5 min) direction on X3 so the left side button
decreases and the right increases, matching the layout. X4 is unchanged.
* Add a device-specific step-hint string
(`STR_SLEEP_TIMER_STEP_HINT_X3`)
selected via `gpio.deviceIsX3()`. X3 shows `+/-: 1 min Side buttons: 5
min`;
X4 keeps the original `Left/Right: 1 min Up/Down: 5 min`.
* Same fix applied to both slider pickers that read the raw up/down side
buttons: the Time-to-Sleep picker and the "Go to %" picker
(`EpubReaderPercentSelectionActivity`), each with its own X3 hint string
(`STR_SLEEP_TIMER_STEP_HINT_X3`, `STR_PERCENT_STEP_HINT_X3`).
## Additional Context
* **Root cause:** the X3's side buttons sit one on each edge of the
screen
(power on top), whereas the X4 has a vertical up/down rocker on the
right
edge. So `BTN_UP` is physically the *left* button on X3 but the *top*
button
on X4. The picker mapped up→+5 / down→−5 unconditionally, which reads
naturally on the X4 rocker but inverted on the X3's left/right buttons.
The
static legend ("Up/Down: 5 min") had the same X3-only mismatch.
* The codebase already detects the device at runtime and handles this
layout
difference elsewhere (e.g. `LyraTheme::drawSideButtonHints` draws "Up on
left,
Down on right" for X3), so this reuses the same `gpio.deviceIsX3()`
signal.
* Swept the codebase for other side-button sliders:
`ClockOffsetActivity` already
uses the `Next/Previous` (`ButtonNavigator`) abstraction, which resolves
to
left=decrement / right=increment on X3, so it needs no change. List/page
navigation (Wi-Fi, KOReader sync, BMP viewer) and the keyboard cursor
are also
unaffected. The two slider pickers above were the only ones using raw
up/down.
* **X4 is untouched** — same direction, same legend wording as before.
* **Tested on X3 hardware:** left side button now decreases, right
increases, and
the legend matches. X4 not yet tested on device (no unit on hand); its
behaviour and strings are unchanged from master.
* **Translations:** the new `STR_SLEEP_TIMER_STEP_HINT_X3` and
`STR_PERCENT_STEP_HINT_X3` were added to all 26 languages, but the
non-English
ones are AI-generated and would benefit from a native-speaker pass —
particularly Hebrew (RTL ordering with a leading `+/-`), Kazakh, and
Vietnamese.
---
### AI Usage
Did you use AI tools to help write this code? _**YES**_
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Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
Justin Mitchell