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fix(ffb): a 64-button virtual wheel, and the debug trace in the log #115

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Merged
mescon merged 1 commit into from
Sep 21, 2026
Merged

fix(ffb): a 64-button virtual wheel, and the debug trace in the log #115

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13 changes: 13 additions & 0 deletions CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,19 @@ changes to the sysfs surface, minor versions add supported wheels or
new attributes, patch versions are bug fixes and documentation. Pre-1.0
the contract is "it works on RS50 and G Pro as listed here".

## Unreleased

**The DirectInput proxy's virtual wheel has 64 buttons, and its debug
trace reaches the log.** The virtual wheel exposed 32 buttons and dropped
the kernel's codes for buttons 17 to 21, which the RS50 never emits but a
G PRO with a shifter does: the higher gears could not be bound in DiRT Rally
2.0 ([#105](../../issues/105)). The report now carries 64 buttons; the
bits the RS50's DirectInput users have already bound stay where they were,
the five recovered buttons follow them, and anything beyond continues from
there. With `LOGI_FFB_DEBUG` set, the proxy's report-level trace now lands
in the launcher log as well as on stderr, which under Steam is the only
place it can be read.

## 0.42.2 - 2026-09-21

**The proxy can open `/dev/uhid` on a machine where nothing else loads
Expand Down
8 changes: 4 additions & 4 deletions userspace/logi-wheel/crates/logi-ffb/src/descriptor.rs
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Expand Up @@ -15,15 +15,15 @@ pub const PRODUCT: u16 = 0xc276;
pub const VIRTUAL_PRODUCT: u16 = 0xc2dd;
pub const VIRTUAL_NAME: &str = "logi-ffb Virtual Wheel";
pub const INPUT_REPORT_ID: u8 = 0x01;
pub const INPUT_REPORT_LEN: usize = 14;
pub const INPUT_REPORT_LEN: usize = 18;

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct InputReport {
pub steering: u16,
pub throttle: u16,
pub brake: u16,
pub clutch: u16,
pub buttons: u32,
pub buttons: u64,
pub hat: u8,
/// Raw hat axis states (-1/0/1), tracked so either axis event can
/// re-derive the 8-way POV value in `hat`; not serialized.
Expand Down Expand Up @@ -80,9 +80,9 @@ const JOYSTICK_PREFIX: &[u8] = &[
0xC0, // End Collection (Physical)
0x05, 0x09, // Usage Page (Button)
0x19, 0x01, // Usage Min (Button 1)
0x29, 0x20, // Usage Max (Button 32)
0x29, 0x40, // Usage Max (Button 64)
0x15, 0x00, 0x25, 0x01, // Logical 0..1
0x75, 0x01, 0x95, 0x20, // 1 bit x 32
0x75, 0x01, 0x95, 0x40, // 1 bit x 64
0x81, 0x02, // Input (buttons)
0x05, 0x01, // Usage Page (Generic Desktop)
0x09, 0x39, // Usage (Hat switch)
Expand Down
18 changes: 9 additions & 9 deletions userspace/logi-wheel/crates/logi-ffb/src/proxy.rs
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Expand Up @@ -381,11 +381,11 @@ impl Proxy {
if debug {
let report_id = bytes.first().copied().unwrap_or(0);
let hex: Vec<String> = bytes.iter().map(|b| format!("{b:02x}")).collect();
eprintln!(
crate::note(&format!(
"logi-ffb: debug: uhid Output len={} report_id={report_id:#04x} bytes={}",
bytes.len(),
hex.join(" ")
);
));
}
if let Some(op) = pidff::decode(&bytes) {
self.dispatch(op);
Expand All @@ -404,7 +404,7 @@ impl Proxy {
// we simply skip creating a block for it.
Ok(uhid::Event::SetReport { rnum: 0x54, rtype, data, id }) => {
if debug {
eprintln!("logi-ffb: debug: uhid SetReport rnum=0x54 rtype={rtype}");
crate::note(&format!("logi-ffb: debug: uhid SetReport rnum=0x54 rtype={rtype}"));
}
if let Some(kind) = data.get(1).and_then(|&b| pidff::effect_kind_from_type_byte(b)) {
let block = assign_block(&mut self.next_block);
Expand All @@ -430,7 +430,7 @@ impl Proxy {
// ack regardless so the kernel is never left waiting.
Ok(uhid::Event::SetReport { rnum, rtype, data, id }) => {
if debug {
eprintln!("logi-ffb: debug: uhid SetReport rnum={rnum:#04x} rtype={rtype}");
crate::note(&format!("logi-ffb: debug: uhid SetReport rnum={rnum:#04x} rtype={rtype}"));
}
if let Some(op) = pidff::decode(&data) {
self.dispatch(op);
Expand All @@ -445,7 +445,7 @@ impl Proxy {
// RAM pool so the host does not treat us as full.
Ok(uhid::Event::GetReport { rnum: 0x56, rtype, id }) => {
if debug {
eprintln!("logi-ffb: debug: uhid GetReport rnum=0x56 rtype={rtype}");
crate::note(&format!("logi-ffb: debug: uhid GetReport rnum=0x56 rtype={rtype}"));
}
let reply = pidff::pid_block_load_reply(self.last_created_block);
if let Err(e) = self.device.send_get_report_reply(id, 0, &reply) {
Expand All @@ -459,7 +459,7 @@ impl Proxy {
// was derived and what is still unconfirmed).
Ok(uhid::Event::GetReport { rnum: 0x57, rtype, id }) => {
if debug {
eprintln!("logi-ffb: debug: uhid GetReport rnum=0x57 rtype={rtype}");
crate::note(&format!("logi-ffb: debug: uhid GetReport rnum=0x57 rtype={rtype}"));
}
let reply = pidff::pid_pool_reply();
if let Err(e) = self.device.send_get_report_reply(id, 0, &reply) {
Expand All @@ -474,7 +474,7 @@ impl Proxy {
// shifted into the report-id position.
Ok(uhid::Event::GetReport { rnum, rtype, id }) => {
if debug {
eprintln!("logi-ffb: debug: uhid GetReport rnum={rnum:#04x} rtype={rtype}");
crate::note(&format!("logi-ffb: debug: uhid GetReport rnum={rnum:#04x} rtype={rtype}"));
}
if let Err(e) = self.device.send_get_report_reply(id, 0, &[rnum]) {
break Err(e);
Expand All @@ -483,13 +483,13 @@ impl Proxy {

Ok(uhid::Event::Open) => {
if debug {
eprintln!("logi-ffb: debug: uhid Open");
crate::note("logi-ffb: debug: uhid Open");
}
}

Ok(uhid::Event::Close) => {
if debug {
eprintln!("logi-ffb: debug: uhid Close");
crate::note("logi-ffb: debug: uhid Close");
}
}

Expand Down
46 changes: 31 additions & 15 deletions userspace/logi-wheel/crates/logi-ffb/src/source.rs
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Expand Up @@ -131,22 +131,27 @@ pub fn map_event(report: &mut InputReport, ev: &input_event) -> bool {
}
}
EV_KEY if ev.code >= BTN_TRIGGER => {
// Two button blocks: the joystick range (BTN_TRIGGER..) maps
// to bits 0-15, and the wheel's extended controls (encoders,
// G1, GL, GR - BTN_TRIGGER_HAPPY range) map to bits 16-31,
// so DirectInput sims can bind them too (issue #50).
// The wheel's extended block starts at BTN_TRIGGER_HAPPY6
// (0x2c5, the first code it actually uses); 0x2c0-0x2c4 are
// unused and dropped to avoid an underflow.
// The kernel numbers a joystick's buttons BTN_TRIGGER+0..15 and
// then BTN_TRIGGER_HAPPY+0.. for the seventeenth onward. The
// layout here keeps every bit the RS50's DirectInput users have
// already bound (issue #50): the joystick range on bits 0-15,
// the RS50's extended block from BTN_TRIGGER_HAPPY6 (0x2c5, its
// first used code: encoders, G1, GL, GR) on bits 16-31. The
// five codes below it, buttons 17-21, were dropped as "unused"
// because the RS50 never emits them; a G PRO with a shifter
// does, and its higher gears could not be bound (#105). They
// now take bits 32-36, and anything past the RS50 block's
// sixteen bits continues from 37, in a 64-button report.
const EXT_FIRST: u16 = BTN_TRIGGER_HAPPY + 5;
let bit = if ev.code >= EXT_FIRST {
16 + (ev.code - EXT_FIRST)
} else if ev.code < BTN_TRIGGER_HAPPY {
ev.code - BTN_TRIGGER
let bit: u32 = if ev.code < BTN_TRIGGER_HAPPY {
(ev.code - BTN_TRIGGER) as u32
} else if ev.code >= EXT_FIRST {
let n = (ev.code - EXT_FIRST) as u32;
if n < 16 { 16 + n } else { 37 + (n - 16) }
} else {
32 // unused 0x2c0-0x2c4: outside both blocks
32 + (ev.code - BTN_TRIGGER_HAPPY) as u32
};
if bit < 32 {
if bit < 64 {
if ev.value != 0 {
report.buttons |= 1 << bit;
} else {
Expand Down Expand Up @@ -242,9 +247,20 @@ mod tests {
assert!(r.buttons & (1 << 16) != 0, "R Encoder CW is bit 16");
assert!(!map_event(&mut r, &ev(EV_KEY, 0x2cd, 1)));
assert!(r.buttons & (1 << 24) != 0, "GR is bit 24");
// Buttons 17-21 (0x2c0-0x2c4), which the RS50 never emits but a
// G PRO with a shifter does (#105), land above the RS50 block so
// nothing already bound moves.
assert!(!map_event(&mut r, &ev(EV_KEY, 0x2c0, 1)));
assert_eq!(r.buttons & 0xFFFF_0000, (1 << 16) | (1 << 24),
"unused 0x2c0-0x2c4 codes map to nothing");
assert!(r.buttons & (1 << 32) != 0, "button 17 (0x2c0) is bit 32");
assert!(!map_event(&mut r, &ev(EV_KEY, 0x2c4, 1)));
assert!(r.buttons & (1 << 36) != 0, "button 21 (0x2c4) is bit 36");
assert_eq!(r.buttons & 0xFFFF_0000, (1 << 16) | (1 << 24), "the RS50 block is unchanged");
// Past the RS50 block's sixteen codes the numbering continues after
// those five, and the report's 64 bits are the ceiling.
assert!(!map_event(&mut r, &ev(EV_KEY, 0x2d5, 1)));
assert!(r.buttons & (1 << 37) != 0, "0x2d5 is bit 37");
assert!(!map_event(&mut r, &ev(EV_KEY, 0x2f0, 1)));
assert_eq!(r.buttons >> 38, 0, "a code past 64 buttons is dropped, not wrapped");
assert_eq!(r.steering, 0x4000);
assert!(map_event(&mut r, &ev(EV_SYN, SYN_REPORT, 0)));
}
Expand Down
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