majorwiki/05-troubleshooting/networking/steam-deck-wifi-flapping-iwd-periodic-scan-rtw88.md

---
title: "Steam Deck Wi-Fi Flapping: IWD Periodic Scan + rtw88 Power Save"
domain: troubleshooting
category: networking
tags: [wifi, steam-deck, steamos, iwd, networkmanager, rtw88, rtl8822ce, power-save, supplicant-disconnect, flapping]
status: published
created: 2026-06-19
updated: 2026-06-19
---

# Steam Deck Wi-Fi Flapping: IWD Periodic Scan + rtw88 Power Save

## 🛑 Problem

An OG Steam Deck (LCD model, Realtek **RTL8822CE** on the `rtw88_8822ce` driver) kept "losing" Wi-Fi — it would connect, hold for around a minute, drop, then reconnect a second later, over and over. From the router side the device looked like it was constantly coming and going; from the couch it felt like the network "wouldn't stay connected."

Crucially, **this was not a router problem.** The AP config was correct, RF was clean (strong signal, zero tx retries / beacon loss), and every other client on the network was rock-solid. The fault was entirely on the Deck.

## 🔍 Diagnosis

SteamOS uses **NetworkManager with the `iwd` backend** (not `wpa_supplicant`). That detail is the whole ballgame.

### Step 1 — Confirm the flap and its cadence

```bash
# how many disconnects this boot?
journalctl -b -u NetworkManager --no-pager | grep -c supplicant-disconnect
# 50

# when did they happen?
journalctl -b -u NetworkManager --no-pager | grep supplicant-disconnect \
  | awk '{print $1,$2,$3}' | tail
# 10:20:52 · 10:21:54 · 10:22:57 · 10:24:00 · 10:25:03 · 10:26:05 · 10:27:08 ...
```

**~63 seconds between every drop.** A fixed, metronome-like interval is the tell — this is a *timer*, not RF noise. The NetworkManager log shows the pattern plainly:

```
activated -> failed (reason 'supplicant-disconnect')
... -> activated         # reconnects ~1s later
```

### Step 2 — Prove the link is healthy *when it's up*

```bash
iw dev wlan0 station dump | grep -iE 'signal|bitrate|failed|retries|beacon loss'
#   signal:    -65 dBm
#   tx retries: 0
#   tx failed:  0
#   beacon loss: 0
```

Strong signal, zero retries, zero beacon loss — the association is clean while it lasts. So the drop is being *commanded*, not caused by a bad radio link.

### Step 3 — Identify the chip and the backend

```bash
lspci -k | grep -A3 -iE 'network|wireless'
#   Realtek RTL8822CE ... Kernel driver in use: rtw88_8822ce
```

The `~63s` interval is **IWD's default periodic background scan**. With no `/etc/iwd/main.conf` present, IWD scans on a timer even while connected, and on the `rtw88` driver that scan knocks the current association over — producing the `supplicant-disconnect` every minute.

A secondary annoyance: `iw dev wlan0 get power_save` reported `on`, which showed up as wildly jittery LAN latency (8–69 ms to the gateway over Wi-Fi, where a healthy 5 GHz link is 2–10 ms).

## ✅ Fix

Two independent changes — the first stops the flap, the second smooths latency.

### 1. Disable IWD's periodic scan (stops the flap)

```bash
sudo mkdir -p /etc/iwd
printf '[Scan]\nDisablePeriodicScan=true\n' | sudo tee /etc/iwd/main.conf
sudo systemctl restart iwd     # briefly drops Wi-Fi; NetworkManager auto-reconnects
```

Trade-off: with periodic scanning off, the Deck roams to a different/stronger AP (e.g. another AiMesh node) more lazily. Fine for a device that mostly sits in one spot.

### 2. Disable Wi-Fi power save (kills the latency jitter)

The obvious `nmcli connection modify <name> 802-11-wireless.powersave 2` **does not work under the IWD backend** — NetworkManager doesn't enforce that property when `iwd` is managing the radio. Use a dispatcher script instead, with a retry loop because `rtw88` won't accept the setting in the first instant after association on a cold boot:

```bash
sudo tee /etc/NetworkManager/dispatcher.d/90-wifi-powersave >/dev/null <<'SCRIPT'
#!/bin/sh
# Disable Wi-Fi power save on the wireless iface (retry: rtw88 may not accept it instantly on boot)
case "$2" in
  up|dhcp4-change|connectivity-change)
    case "$1" in
      wl*)
        for n in 1 2 3 4 5; do
          /usr/bin/iw dev "$1" set power_save off 2>/dev/null
          [ "$(/usr/bin/iw dev "$1" get power_save 2>/dev/null)" = "Power save: off" ] && break
          sleep 1
        done
      ;;
    esac
  ;;
esac
SCRIPT
sudo chmod +x /etc/NetworkManager/dispatcher.d/90-wifi-powersave
sudo iw dev wlan0 set power_save off    # apply now without waiting for a reconnect
```

> 💡 A single-shot dispatcher (no retry) **silently fails on a cold boot** — it fires before the interface is ready, the `iw` call no-ops, and power save stays on. Verify with `iw get power_save` *after a real reboot*, not just after a service restart.

## 🔁 Verification

```bash
# was 50/boot, ~once a minute:
journalctl -b -u NetworkManager --no-pager | grep -c supplicant-disconnect
# 0
iw dev wlan0 get power_save
# Power save: off
```

A 3-minute continuous `ping` showed **180/180 replies, 0 loss**, latency tightened to **6–11 ms**. Confirmed across a full cold reboot: the Deck auto-rejoins Wi-Fi, both settings persist, and the disconnect counter stays at 0.

## 📌 Notes

- **Persistence:** `/etc/iwd/main.conf` and the dispatcher live in `/etc`, which survives reboots. A major SteamOS update *can* reset `/etc` — re-apply if the flapping returns after an OS update.
- **Fully reversible:**
  ```bash
  sudo rm /etc/iwd/main.conf /etc/NetworkManager/dispatcher.d/90-wifi-powersave
  sudo systemctl restart iwd
  ```
- **Interface name** is usually `wlan0`; confirm with `iw dev` if different.
- The same IWD-periodic-scan behavior can affect other `iwd`-based distros (Arch, some Fedora spins) on flaky/older Wi-Fi chips — the `DisablePeriodicScan` fix is general, not Deck-specific.

## 🔗 Related

- [Wi-Fi Game Streaming Stutter: 160 MHz Channel Width Saturating the 5 GHz Radio](wifi-160mhz-airtime-saturation-game-streaming.md) — the *other* Steam Deck Wi-Fi issue (airtime contention, router-side), distinct from this client-side flap.