Andreas WredeandClaude Sonnet 5
a1bad186b1
Seen after moving the modem onto the new powered UGreen hub: the port sometimes never signals a connect during boot (no descriptor-read attempt at all in dmesg), so the hub never rescans it. Unbind/rebinding the inner hub chip reproduces the same connect edge a physical unplug/replug does. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
120 lines
4.7 KiB
Python
Executable File
120 lines
4.7 KiB
Python
Executable File
#!/usr/bin/env python3
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"""van-modem-usb-kick — recover the EC25 modem when it's missing after boot.
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Seen on 2026-08-04, right after moving the modem onto the new powered UGreen
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hub: the 5GHz AP (rtw89, on the hub's outer USB chip) and the hub's built-in
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Ethernet (AX88179, on its inner cascaded USB2.1 hub chip) both enumerate
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cleanly at boot, but the EC25 modem — plugged into a port on that same inner
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hub chip — sometimes never does, even though it has power (LED on). dmesg
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shows no connect attempt at all for the modem's port during boot (contrast
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the Ethernet's clean enumeration, or the AP's one-shot retry after a
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descriptor-read error) — the port just never signalled a connect in time, and
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a hub only rescans a port on an actual connect/disconnect edge, so it stays
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invisible until something produces one. Physically unplugging/replugging
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either the whole hub or just the modem fixes it immediately, because both
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produce that edge. This script produces the same edge in software: unbind
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then rebind the inner hub chip's kernel driver, which forces it to redo
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enumeration of everything on it (the modem, and briefly the Starlink
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Ethernet — the AP is on the outer chip and is undisturbed).
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The inner hub is found by walking up from STARLINK_IFACE's sysfs device (it's
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the Ethernet's parent hub) rather than hardcoding a bus/port path, since that
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identifies "the hub carrying the modem" without assuming a specific topology.
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Bounded to a few minutes after boot, then exits — this is a boot-race
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backstop, not a permanent watcher (a modem physically removed later should
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just stay gone, not get fought).
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Usage: van-modem-usb-kick [modem-usb-vendor] [starlink-iface]
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Defaults to 2c7c (Quectel) and enx6c1ff7d210a5 — see deploy.conf.
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"""
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import sys
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import time
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from pathlib import Path
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MODEM_VENDOR = sys.argv[1] if len(sys.argv) > 1 else "2c7c"
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STARLINK_IFACE = sys.argv[2] if len(sys.argv) > 2 else "enx6c1ff7d210a5"
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INTERVAL = 20 # seconds between checks
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BUDGET_S = 6 * INTERVAL # ~2 minutes of retries after boot, then give up quietly
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USB_DEVICES = Path("/sys/bus/usb/devices")
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HUB_DRIVER = Path("/sys/bus/usb/drivers/hub")
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def log(msg, level="info"):
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# systemd journal severity prefixes (sd-daemon), same convention as van-ap-watchdog.
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pri = {"info": "<6>", "warn": "<4>", "crit": "<2>"}.get(level, "<6>")
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print(pri + msg, flush=True)
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def modem_present(vendor):
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for f in USB_DEVICES.glob("*/idVendor"):
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try:
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if f.read_text().strip() == vendor:
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return True
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except OSError:
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continue
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return False
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def inner_hub_name(starlink_iface):
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"""sysfs driver-name (e.g. '2-1.4') of the USB hub carrying starlink_iface —
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that's the same hub chip the modem's port is on. None if the Ethernet
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itself hasn't enumerated (nothing to walk up from)."""
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dev = Path(f"/sys/class/net/{starlink_iface}/device")
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if not dev.exists():
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return None
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# dev resolves to .../<hub>/<hub>.<port>/<hub>.<port>:<config>.<iface>
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# (e.g. .../2-1.4/2-1.4.2/2-1.4.2:2.0) — two levels up is the hub itself.
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hub = dev.resolve().parent.parent
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if not (hub / "bDeviceClass").exists():
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return None
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try:
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if hub.joinpath("bDeviceClass").read_text().strip() != "09": # 09 = hub
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return None
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except OSError:
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return None
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return hub.name
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def kick(hub_name):
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log(f"modem (vendor {MODEM_VENDOR}) absent — rebinding hub {hub_name} to force "
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f"re-enumeration (same effect as unplug/replug; briefly bounces {STARLINK_IFACE})",
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"warn")
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try:
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(HUB_DRIVER / "unbind").write_text(hub_name)
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time.sleep(2)
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(HUB_DRIVER / "bind").write_text(hub_name)
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except OSError as e:
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log(f"hub rebind failed: {e}", "warn")
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def main():
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log(f"van-modem-usb-kick up: watching for USB vendor {MODEM_VENDOR} for up to "
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f"{BUDGET_S}s after boot")
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elapsed = 0
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kicked = False
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while elapsed < BUDGET_S:
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if modem_present(MODEM_VENDOR):
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log("modem present — exiting" + (" (recovered)" if kicked else ""))
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return
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if not kicked:
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hub_name = inner_hub_name(STARLINK_IFACE)
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if hub_name:
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kick(hub_name)
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kicked = True
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# else: Ethernet itself isn't up yet — give the system more time
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# before assuming anything is wrong.
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time.sleep(INTERVAL)
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elapsed += INTERVAL
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if not modem_present(MODEM_VENDOR):
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log(f"modem still absent after {BUDGET_S}s — giving up "
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f"(leaving it for manual unplug/replug from here on)", "warn")
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if __name__ == "__main__":
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try:
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main()
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except KeyboardInterrupt:
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sys.exit(0)
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