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fix(uvc): preserve control event fairness

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This commit is contained in:
Brad Stein 2026-08-13 02:57:02 -03:00
parent 2621f7dead
commit 2a5f059a0b
11 changed files with 119 additions and 19 deletions
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6
Cargo.lock generated
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@ -1658,7 +1658,7 @@ checksum = "09edd9e8b54e49e587e4f6295a7d29c3ea94d469cb40ab8ca70b288248a81db2"
[[package]]
name = "lesavka_client"
version = "0.27.9"
version = "0.27.10"
dependencies = [
"anyhow",
"async-stream",
@ -1692,7 +1692,7 @@ dependencies = [
[[package]]
name = "lesavka_common"
version = "0.27.9"
version = "0.27.10"
dependencies = [
"anyhow",
"base64",
@ -1704,7 +1704,7 @@ dependencies = [
[[package]]
name = "lesavka_server"
version = "0.27.9"
version = "0.27.10"
dependencies = [
"anyhow",
"base64",

2
client/Cargo.toml
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@ -4,7 +4,7 @@ path = "src/main.rs"
[package]
name = "lesavka_client"
version = "0.27.9"
version = "0.27.10"
edition = "2024"
[dependencies]

2
common/Cargo.toml
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@ -1,6 +1,6 @@
[package]
name = "lesavka_common"
version = "0.27.9"
version = "0.27.10"
edition = "2024"
build = "build.rs"

24
docs/architecture-and-media-readiness.md
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@ -314,7 +314,19 @@ into the Lesavka tree, installs it with the server, requires `libgpiod`, and
runs it with `/usr/bin/python` before capture discovery. This removes the
unversioned virtualenv from the physical eye-feed power path.
## 7. The Current Downstream Video Failure
### The `0.27.10` UVC Event-Fairness Fix
The first post-repair synthetic upstream probe reached Tethys but produced no
decodable MJPEG timeline. Tethys recorded repeated `EOI before SOF` packets and
two five-second UVC probe-control timeouts. The helper drained completed V4L2
output buffers without a per-turn bound before servicing control events, so a
continuously consuming host could starve probe/commit traffic. Release 0.27.10
bounds dequeue work, reports fairness yields, and makes the native receiver
probe terminate with evidence even when malformed packets produce no decoded
timestamps. This is a hardware-testable correction; marked Tethys capture is
still required before declaring the tear/smear class fixed.
## 7. The Resolved Downstream Video Failure
The current blank downstream feeds fail before transport or decoding.
@ -369,6 +381,10 @@ successfully imported the installed `libgpiod` binding. This proves the common
downstream failure was capture-card power automation, not two simultaneous
card failures, H.264 transport, or client decoding. Release 0.27.9 makes the
working system binding and a versioned helper the installed service contract.
After installing 0.27.9, GPIO27 stayed asserted, both GC311 devices enumerated,
and both downstream RPCs decoded 1280x720 H.264. The right eye carried changing
desktop video; the left eye carried the capture card's explicit `No Signal`
frame, isolating that remaining input condition to its HDMI source/cable.
## 8. Recovery And Deployment Sequence
@ -386,7 +402,7 @@ The safe completion sequence for this incident is:
6. Run `scripts/install/server.sh` as the trusted deployment path. Preserve the
already-attached USB gadget unless a controlled rebuild is explicitly
required.
7. Confirm Theia reports server version `0.27.9`, the pushed release revision,
7. Confirm Theia reports server version `0.27.10`, the pushed release revision,
direct MJPEG normalizer timeout `0`, and a coherent UVC contract.
8. Open both downstream RPCs and prove that each emits changing, decodable H.264
frames.
@ -404,7 +420,7 @@ hardware contract is repeatable. The remaining work falls into five groups.
### A. Install And Version Parity
- Push and deploy `0.27.9` through the client/server install scripts.
- Push and deploy `0.27.10` through the client/server install scripts.
- Confirm client/server version and revision in every hardware probe artifact.
- Eliminate the current state where a fixed client talks to an unfixed server.
@ -470,6 +486,6 @@ host repair:
9. disconnect/reconnect and device changes recover without stale media; and
10. diagnostics identify the failed physical stage when any item breaks.
Until that sequence passes on the installed `0.27.9` client/server pair, the
Until that sequence passes on the installed `0.27.10` client/server pair, the
current release should be described as a validated code correction awaiting
hardware deployment and end-to-end acceptance, not as a completed product fix.

1
scripts/install/server.sh
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@ -418,6 +418,7 @@ LESAVKA_UVC_WIDTH=$(uvc_env_value LESAVKA_UVC_WIDTH 1280)
LESAVKA_UVC_HEIGHT=$(uvc_env_value LESAVKA_UVC_HEIGHT 720)
LESAVKA_UVC_CODEC=${INSTALL_UVC_CODEC}
LESAVKA_UVC_BUFFER_COUNT=$(uvc_env_value LESAVKA_UVC_BUFFER_COUNT 4)
LESAVKA_UVC_PUMP_DEQUEUE_BUDGET=$(uvc_env_value LESAVKA_UVC_PUMP_DEQUEUE_BUDGET 4)
LESAVKA_UVC_BLOCKING=$(uvc_env_value LESAVKA_UVC_BLOCKING 1)
LESAVKA_UVC_CONTROL_READ_ONLY=$(uvc_env_value LESAVKA_UVC_CONTROL_READ_ONLY 0)
LESAVKA_UVC_QUEUE_PACING=$(uvc_env_value LESAVKA_UVC_QUEUE_PACING 0)

28
scripts/manual/run_synthetic_rct_uvc_probe.py
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@ -1672,8 +1672,8 @@ def run_capture(args: argparse.Namespace) -> int:
command, capture_width, capture_height, device = ffmpeg_cmd(args, width, height)
artifact_dir = pathlib.Path(args.artifact_dir) if args.artifact_dir else pathlib.Path("/tmp") / f"lesavka-synthetic-rct-capture-{timestamp()}"
artifact_dir.mkdir(parents=True, exist_ok=True)
if args.deep_capture and args.source != "uvc":
raise SystemExit("--deep-capture requires --source uvc")
if args.deep_capture and args.source != "device":
raise SystemExit("--deep-capture requires --source device")
if args.deep_capture:
write_deep_capture_snapshot(artifact_dir, "before", device)
dynamic_debug_enabled = (
@ -1688,6 +1688,7 @@ def run_capture(args: argparse.Namespace) -> int:
analysis_elapsed = 0.0
raw_capture_bytes = 0
ffmpeg_rc: int | None = None
capture_timed_out = False
frame_index = 0
suspicious_count = 0
visual_suspicious_count = 0
@ -1807,11 +1808,26 @@ def run_capture(args: argparse.Namespace) -> int:
capture_command[-1:-1] = ["-t", str(args.duration)]
capture_command[-1] = str(raw_path)
(artifact_dir / "command.txt").write_text(" ".join(shlex.quote(part) for part in capture_command) + "\n")
print(f"capturing raw RCT frames before analysis: {raw_path}", file=sys.stderr)
capture_target = native_mjpeg if native_mjpeg is not None else raw_path
print(f"capturing RCT frames before analysis: {capture_target}", file=sys.stderr)
capture_started = time.monotonic()
proc = subprocess.run(capture_command, stdout=subprocess.DEVNULL, stderr=err, check=False)
try:
proc = subprocess.run(
capture_command,
stdout=subprocess.DEVNULL,
stderr=err,
check=False,
timeout=max(5.0, args.duration + 10.0),
)
ffmpeg_rc = proc.returncode
except subprocess.TimeoutExpired:
capture_timed_out = True
ffmpeg_rc = 124
err.write(
f"capture exceeded wall timeout after {args.duration + 10.0:.1f}s\n".encode()
)
err.flush()
capture_elapsed = time.monotonic() - capture_started
ffmpeg_rc = proc.returncode
if args.deep_capture and native_mjpeg is not None and native_mjpeg.exists():
decode_command = [
"ffmpeg", "-hide_banner", "-nostdin", "-loglevel", "warning",
@ -1819,6 +1835,7 @@ def run_capture(args: argparse.Namespace) -> int:
]
(artifact_dir / "decode-command.txt").write_text(" ".join(shlex.quote(part) for part in decode_command) + "\n")
subprocess.run(decode_command, stdout=subprocess.DEVNULL, stderr=err, check=False)
raw_path.touch(exist_ok=True)
raw_capture_bytes = raw_path.stat().st_size if raw_path.exists() else 0
print(
f"analyzing captured raw RCT frames bytes={raw_capture_bytes} capture_s={capture_elapsed:.3f}",
@ -1855,6 +1872,7 @@ def run_capture(args: argparse.Namespace) -> int:
"duration_observed_s": round(elapsed, 3),
"analysis_duration_s": round(analysis_elapsed, 3),
"ffmpeg_rc": ffmpeg_rc,
"capture_timed_out": capture_timed_out,
"raw_capture_bytes": raw_capture_bytes,
"frames": frame_index,
"fps_observed": round(frame_index / elapsed, 3),

2
server/Cargo.toml
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@ -16,7 +16,7 @@ bench = false
[package]
name = "lesavka_server"
version = "0.27.9"
version = "0.27.10"
edition = "2024"
autobins = false

22
server/src/bin/lesavka-uvc.real.inc
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@ -53,6 +53,7 @@ const IDLE_MJPEG_FRAME: &[u8] = include_bytes!("lesavka_uvc/idle_1280x720_black.
// Keep enough output buffers queued that the USB gadget is not starved while a
// browser is consuming high-speed isochronous MJPEG.
const DEFAULT_UVC_BUFFER_COUNT: u32 = 4;
const DEFAULT_UVC_PUMP_DEQUEUE_BUDGET: usize = 4;
const DEFAULT_UVC_IDLE_PUMP_MS: u64 = 2;
const DEFAULT_UVC_FRAME_MAX_AGE_MS: u64 = 1_000;
const DEFAULT_UVC_QUEUE_PACING: bool = false;
@ -292,6 +293,7 @@ struct UvcVideoStats {
last_rejected_oversize_cap: usize,
paced_sleeps: u64,
paced_sleep_ms: u64,
pump_budget_yields: u64,
last_report: Option<Instant>,
}
@ -380,7 +382,7 @@ impl UvcVideoStream {
if !self.streaming {
return Ok(());
}
loop {
for _ in 0..uvc_pump_dequeue_budget() {
let mut buf = empty_v4l2_buffer();
let req = ioctl_readwrite::<V4l2Buffer>(b'V', 17);
let rc = unsafe { libc::ioctl(self.fd, req, &mut buf) };
@ -399,6 +401,8 @@ impl UvcVideoStream {
}
self.queue_buffer(buf.index, buf.flags)?;
}
self.stats.pump_budget_yields += 1;
Ok(())
}
fn set_format(&self, cfg: UvcConfig) -> Result<()> {
@ -684,7 +688,7 @@ impl UvcVideoStream {
}
self.stats.last_report = Some(now);
eprintln!(
"[lesavka-uvc] video stats queued={} reloaded={} stale_replay={} rejected_oversize={} rejected_invalid={} fallback_idle={} held_last_good={} read_errors={} strict_validation_failures={} dqbuf_ioctl_errors={} dqbuf_flag_errors={} qbuf_ioctl_errors={} latest_bytes={} frame_cap={} last_rejected_oversize_bytes={} last_rejected_oversize_cap={} paced_sleeps={} paced_sleep_ms={}",
"[lesavka-uvc] video stats queued={} reloaded={} stale_replay={} rejected_oversize={} rejected_invalid={} fallback_idle={} held_last_good={} read_errors={} strict_validation_failures={} dqbuf_ioctl_errors={} dqbuf_flag_errors={} qbuf_ioctl_errors={} latest_bytes={} frame_cap={} last_rejected_oversize_bytes={} last_rejected_oversize_cap={} paced_sleeps={} paced_sleep_ms={} pump_budget_yields={}",
self.stats.queued,
self.stats.reloaded,
self.stats.replayed_stale,
@ -702,7 +706,8 @@ impl UvcVideoStream {
self.stats.last_rejected_oversize_bytes,
self.stats.last_rejected_oversize_cap,
self.stats.paced_sleeps,
self.stats.paced_sleep_ms
self.stats.paced_sleep_ms,
self.stats.pump_budget_yields
);
if let Some(path) = uvc_stats_path() {
let _ = write_atomic_text(
@ -778,6 +783,14 @@ fn uvc_buffer_count() -> u32 {
env_u32("LESAVKA_UVC_BUFFER_COUNT", DEFAULT_UVC_BUFFER_COUNT).clamp(1, 8)
}
fn uvc_pump_dequeue_budget() -> usize {
env_u64(
"LESAVKA_UVC_PUMP_DEQUEUE_BUDGET",
DEFAULT_UVC_PUMP_DEQUEUE_BUDGET as u64,
)
.clamp(1, 64) as usize
}
fn uvc_idle_pump_sleep() -> Duration {
Duration::from_millis(env_u64(
"LESAVKA_UVC_IDLE_PUMP_MS",
@ -903,7 +916,7 @@ fn write_atomic_text(path: &std::path::Path, text: &str) -> Result<()> {
fn uvc_stats_snapshot_json(stats: &UvcVideoStats, frame_cap: usize) -> String {
let kernel = uvc_kernel_stats_json();
format!(
"{{\"generated_unix_ms\":{},\"queued\":{},\"reloaded\":{},\"stale_replay\":{},\"rejected_oversize\":{},\"rejected_invalid\":{},\"fallback_idle\":{},\"held_last_good\":{},\"read_errors\":{},\"strict_validation_failures\":{},\"dqbuf_ioctl_errors\":{},\"dqbuf_flag_errors\":{},\"qbuf_ioctl_errors\":{},\"latest_bytes\":{},\"frame_cap\":{},\"last_rejected_oversize_bytes\":{},\"last_rejected_oversize_cap\":{},\"paced_sleeps\":{},\"paced_sleep_ms\":{},\"kernel\":{}}}\n",
"{{\"generated_unix_ms\":{},\"queued\":{},\"reloaded\":{},\"stale_replay\":{},\"rejected_oversize\":{},\"rejected_invalid\":{},\"fallback_idle\":{},\"held_last_good\":{},\"read_errors\":{},\"strict_validation_failures\":{},\"dqbuf_ioctl_errors\":{},\"dqbuf_flag_errors\":{},\"qbuf_ioctl_errors\":{},\"latest_bytes\":{},\"frame_cap\":{},\"last_rejected_oversize_bytes\":{},\"last_rejected_oversize_cap\":{},\"paced_sleeps\":{},\"paced_sleep_ms\":{},\"pump_budget_yields\":{},\"kernel\":{}}}\n",
unix_now_ns() / 1_000_000,
stats.queued,
stats.reloaded,
@ -923,6 +936,7 @@ fn uvc_stats_snapshot_json(stats: &UvcVideoStats, frame_cap: usize) -> String {
stats.last_rejected_oversize_cap,
stats.paced_sleeps,
stats.paced_sleep_ms,
stats.pump_budget_yields,
kernel
)
}

1
tests/contract/scripts/install/server_install_script_contract.rs
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@ -276,6 +276,7 @@ fn server_install_pins_hdmi_camera_and_display_defaults() {
assert!(SERVER_INSTALL.contains("uvc_env_value LESAVKA_UVC_HEIGHT 720"));
assert!(SERVER_INSTALL.contains("uvc_env_value LESAVKA_UVC_CONTROL_READ_ONLY 0"));
assert!(SERVER_INSTALL.contains("uvc_env_value LESAVKA_UVC_BUFFER_COUNT 4"));
assert!(SERVER_INSTALL.contains("uvc_env_value LESAVKA_UVC_PUMP_DEQUEUE_BUDGET 4"));
assert!(SERVER_INSTALL.contains("uvc_env_value LESAVKA_UVC_QUEUE_PACING 0"));
assert!(SERVER_INSTALL.contains("uvc_env_value LESAVKA_UVC_BULK 1"));
assert!(SERVER_INSTALL.contains("uvc_env_value LESAVKA_UVC_FRAME_SIZE_GUARD 1"));

20
tests/contract/server/uvc/server_uvc_binary_contract.rs
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@ -376,6 +376,24 @@ mod uvc_binary {
assert!(source.contains("streaming_bulk is not 1; using isochronous payload sizing"));
}
#[test]
#[serial]
fn uvc_video_pump_is_bounded_so_control_requests_cannot_starve() {
with_var("LESAVKA_UVC_PUMP_DEQUEUE_BUDGET", None::<&str>, || {
assert_eq!(uvc_pump_dequeue_budget(), 4);
});
with_var("LESAVKA_UVC_PUMP_DEQUEUE_BUDGET", Some("1"), || {
assert_eq!(uvc_pump_dequeue_budget(), 1);
});
with_var("LESAVKA_UVC_PUMP_DEQUEUE_BUDGET", Some("999"), || {
assert_eq!(uvc_pump_dequeue_budget(), 64);
});
let source = include_str!("../../../../server/src/bin/lesavka-uvc.real.inc");
assert!(source.contains("for _ in 0..uvc_pump_dequeue_budget()"));
assert!(source.contains("self.stats.pump_budget_yields += 1"));
}
#[test]
#[serial]
fn uvc_stats_snapshot_can_be_disabled_or_written() {
@ -397,6 +415,7 @@ mod uvc_binary {
last_rejected_oversize_cap: 300_000,
paced_sleeps: 5,
paced_sleep_ms: 123,
pump_budget_yields: 11,
last_report: None,
};
let json = uvc_stats_snapshot_json(&stats, 333_333);
@ -407,6 +426,7 @@ mod uvc_binary {
assert!(json.contains("\"last_rejected_oversize_cap\":300000"));
assert!(json.contains("\"paced_sleeps\":5"));
assert!(json.contains("\"paced_sleep_ms\":123"));
assert!(json.contains("\"pump_budget_yields\":11"));
let kernel_path = tempfile::NamedTempFile::new().expect("kernel stats");
fs::write(

30
tests/manual/server/rct/synthetic_rct_uvc_probe_manual_contract.rs
View File

@ -152,6 +152,36 @@ fn synthetic_probe_keeps_bundled_network_ingress_and_rct_comparison_markers() {
}
}
#[test]
fn synthetic_probe_deep_capture_accepts_its_device_source_mode() {
assert!(
PROBE_SRC.contains("if args.deep_capture and args.source != \"device\":")
&& PROBE_SRC.contains("--deep-capture requires --source device"),
"deep capture must accept the parser's UVC device source instead of requiring an unavailable source name"
);
assert!(
!PROBE_SRC.contains("--deep-capture requires --source uvc"),
"the probe must not demand a source name its argument parser rejects"
);
}
#[test]
fn synthetic_probe_capture_has_a_wall_clock_timeout() {
for expected in [
"timeout=max(5.0, args.duration + 10.0)",
"except subprocess.TimeoutExpired:",
"capture_timed_out = True",
"ffmpeg_rc = 124",
"raw_path.touch(exist_ok=True)",
"\"capture_timed_out\": capture_timed_out",
] {
assert!(
PROBE_SRC.contains(expected),
"receiver capture must terminate and report evidence even when malformed UVC packets produce no decoded timeline: {expected}"
);
}
}
#[test]
fn synthetic_injector_enters_the_public_bundled_media_rpc() {
for expected in [