fix: self-heal the LCD after USB write failures (reconnect + open() correctness)#2
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tekgnosis-net wants to merge 5 commits into
Open
fix: self-heal the LCD after USB write failures (reconnect + open() correctness)#2tekgnosis-net wants to merge 5 commits into
tekgnosis-net wants to merge 5 commits into
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Pure, hardware-free state machine for failure-streak demote/reconnect decisions, exit-to-systemd timing, and throttled error logging. 7 unit tests.
lcd_failure_threshold, lcd_reconnect_interval_ms, lcd_exit_after_ms, lcd_error_log_interval_ms with sane defaults.
…back Interface 1 is the only display interface (output-only, no hidraw node). The old devices.first() fallback could open interface 0 (input device).
…hrottle) Record every device write outcome into LcdHealth. On a sustained failure streak, drop the handle to None (releasing the libusb claim) so the existing try_lcd_reconnect() reopens it; throttle the error log; and exit-to-systemd as a last resort. Replaces error-propagation at the heartbeat/render call sites.
Replace the hard-coded 30s reconnect rate-limit with lcd_reconnect_interval_ms (default 5s) for faster recovery. The main.rs loop log-throttle is already correct as of 0.8.1, so it is left unchanged.
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Problem
The daemon opens the LCD once at startup. If the device hits a USB write failure or re-enumerates mid-run, nothing re-establishes it — the panel reverts to its built-in default screen and stays there until the service is manually restarted. The existing
try_lcd_reconnect()only triggers when the device was absent at startup (lcd == None); it never fires for a device that was working and then dropped, because nothing ever sets the handle back toNone.Changes
LcdHealth— a small, hardware-free state machine that tracks consecutive write outcomes. After N consecutive failures (default 10) it demotes the handle toNone(dropping theHidDevicereleases the libusb interface claim), which lets the existingtry_lcd_reconnect()reopen the device. If recovery keeps failing past a configurable window, it exits sosystemdrelaunches a fresh process. Transient single failures (interspersed with successes) never trip the threshold.open()correctness — require the display interface (interface 1, output-only) and drop the fallback that could open the wrong (input) interface.lcd_failure_threshold,lcd_reconnect_interval_ms,lcd_exit_after_ms,lcd_error_log_interval_ms).hidrawnode, so hidraw can't drive it.Testing
LcdHealthlogic (threshold, success-reset, exit-only-after-connect, log throttle) — pure, deterministic, no hardware.authorized=0/1; observeddemote after 10 failures → reopen interface 1 → reconnected, fully in-process (no restart).cargo test+clippy -D warningsclean.