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diff --git a/docs/BAYCOM-FREEZES.md b/docs/BAYCOM-FREEZES.md new file mode 100644 index 0000000..5b63e81 --- /dev/null +++ b/docs/BAYCOM-FREEZES.md @@ -0,0 +1,40 @@ +# BayCom/based — host freeze warning (RX / TX) + +**MAX25-Stack** · **BayCom/based** SER12 class (PC-COM / TCM3105) + +**Status:** BayCom/based is **available · usable** (default build ON). This page documents **freeze risk** on some hosts — especially legacy kernel paths and EMI near interactive desktops. Current product uses userspace **max25-bcpr**. + +> **Warning:** On some hosts (especially interactive desktops), **RX and TX** with BayCom/based PC-COM-class hardware can **hard-freeze** or soft-hang the machine — historically observed with kernel `baycom_ser_fdx`. Treat SQ-open / strong RF / USB HID hubs as risk. + +## Freeze classes + +| Class | Typical trigger | Radio needed? | +|-------|-----------------|---------------| +| **TX / calibrate (legacy kernel)** | `baycom_test calibrate N`, HDLC calibrate ioctl | **No** — observed with radio **off** | +| **RX / RF EMI** | Peer packet TX / strong RF near the PC; USB HID dropout (`EMI?` in `dmesg`) | Over-air RF; can freeze **even if** no modem driver is loaded | +| Soft hang | High UART IRQ bitbang load; brief input/USB stall | Often radio off | + +Kernel `baycom_ser_fdx` / `baycom-pr` was **removed** from this tree (2026-07-18). Do **not** reintroduce calibrate against `bcsf*` on interactive desktops. + +## Forbidden / high risk on interactive desktops + +| Do not | Why | +|--------|-----| +| Load `baycom_ser_fdx` / run calibrate helpers | Instant hard freeze observed on interactive hosts | +| Hot-plug radio/mic cables while any path owns the UART | Freeze risk | +| Leave stack up unattended next to live RF | EMI class | + +## Safer practice (experimental opt-in only) + +| Do | Notes | +|----|--------| +| Prefer a **dedicated / minimal** host when RF is strong | Reduces EMI freeze class on interactive desktops | +| Unplug AF / power radio off when not testing | Reduces EMI class | +| Move keyboard/mouse to motherboard USB ports | Avoid front/shared hubs near RF | + +## Related + +| Topic | Path | +|-------|------| +| BayCom/based status | [BAYCOM.md](BAYCOM.md) | +| Unified TX/RX release test | [TX-RX-TEST.md](TX-RX-TEST.md) · `scripts/tx-rx-test.sh` | |