vndangkhoa/vietc
1
0
Fork 0
Code Issues Pull requests Projects Releases 1 Packages Wiki Activity Actions 1

fix: VM keyboard EV_KEY+EV_MSC double-processing in non-grabbed mode

Browse source 
VM keyboards emit both EV_KEY and EV_MSC/MSC_SCAN events for each
physical key press. The non-grabbed evdev loop was processing both,
causing each character to be processed twice by the engine. This
doubled every character in the engine buffer, corrupting the output.

Fix: collect EV_KEY keycodes first, then skip MSC_SCAN events that
map to already-processed EV_KEY keycodes. Only VMs that emit
MSC_SCAN without EV_KEY still process the MSC fallback.

Also removed spammy 'evdev: N device(s) have events after ungrab' log
that flooded the terminal on every poll iteration.
This commit is contained in:
Khoa Vo 2026-07-04 16:25:19 +07:00
parent ed23d6bc35
commit 6756340cb0
1 changed files with 17 additions and 13 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

30
daemon/src/main.rs
View file

@ -1412,13 +1412,6 @@ fn run_with_evdev(
}
idle_polls = 0;
if !grabbed {
log_info(&format!(
"[vietc] evdev: {} device(s) have events after ungrab",
pfds.iter().filter(|p| (p.revents & libc::POLLIN) != 0).count()
));
}
// Check for status changes instantly
if status_changed.load(Ordering::SeqCst) {
daemon.sync_status_file();
@ -1441,8 +1434,8 @@ fn run_with_evdev(
let caps = device_states[i].1;
let mut key_state = std::mem::take(&mut device_states[i].0);
let events = match device.fetch_events() {
Ok(events) => events,
let event_list = match device.fetch_events() {
Ok(events) => events.collect::<Vec<_>>(),
Err(e) => {
if e.kind() == std::io::ErrorKind::Interrupted {
continue;
@ -1456,9 +1449,17 @@ fn run_with_evdev(
};
last_event_time = std::time::Instant::now();
// Collect all EV_KEY keycodes first so we can skip redundant MSC_SCAN events
let mut key_processed: HashSet<u16> = HashSet::new();
for event in &event_list {
if event.event_type() == evdev::EventType::KEY {
key_processed.insert(event.code());
}
}
// Cache last MSC_SCAN keycode (VM workaround: some VMs emit EV_MSC instead of EV_KEY)
let mut last_msc_code: Option<u16> = None;
for event in events {
for event in event_list {
let ev_type = event.event_type();
let ev_code = event.code();
let ev_value = event.value();
@ -1473,14 +1474,17 @@ fn run_with_evdev(
let (keycode_val, value) = if is_key {
(ev_code, ev_value)
} else {
// MSC_SCAN contains Linux keycode in value. MSC events come in
// pairs: first = press, second = release (same value).
// MSC_SCAN contains Linux keycode in value.
// Skip if this keycode was already processed as EV_KEY.
let scan_code = ev_value as u16;
if key_processed.contains(&scan_code) {
continue;
}
let is_press = last_msc_code.map_or(true, |prev| prev != ev_code);
last_msc_code = Some(ev_code);
if !is_press {
continue;
}
// Extract Linux keycode from MSC_SCAN value; treat as press
let code = if ev_value >= 0 && ev_value <= KEY_MAX as i32 {
ev_value as u16
} else {