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Known Issues

This document tracks ongoing issues with the MediaTek MT7925 WiFi driver that are partially mitigated by the patches in this repository but may have root causes in the firmware itself.

Issue #1: MCU Timeout During MLO Roaming
Status Partially Mitigated
Severity Medium
First Observed January 2026
Firmware WM Build 20250721232943

Summary

During WiFi 7 MLO (Multi-Link Operation) roaming attempts, the MT7925 firmware can become unresponsive, causing MCU command timeouts. The driver now recovers gracefully (thanks to our patches), but the underlying firmware issue remains.

Symptoms

MCU message timeouts in dmesg:

mt7925e 0000:c0:00.0: Message 00020002 (seq 12) timeout
mt7925e 0000:c0:00.0: Message 00020003 (seq 13) timeout
mt7925e 0000:c0:00.0: Message 00020002 (seq 14) timeout
  • Firmware reset/reload occurs automatically
  • Brief WiFi disconnection (~30 seconds)
  • Successful reconnection after recovery

Trigger Conditions

  1. WiFi 7 AP with MLO enabled (multiple bands: 2.4GHz + 5GHz + 6GHz)
  2. MT7925 client with MLO active on multiple links
  3. Roaming triggered between BSSIDs (signal-based or manual)
  4. Particularly common when switching to/from 6GHz band

Root Cause Analysis

The roaming failure cascade involves multiple issues:

1. MLO Group Key Removal Returns -EINVAL

wlp192s0: failed to remove key (1, ff:ff:ff:ff:ff:ff) from hardware (-22)
wlp192s0: failed to remove key (4, ff:ff:ff:ff:ff:ff) from hardware (-22)

The driver returns -EINVAL when removing broadcast/multicast keys during MLO roaming. This suggests the key removal path doesn't properly handle MLO link IDs.

wpa_supplicant reports: 

nl80211: kernel reports: link ID must for MLO group key

2. BSS Fetch Failure

nl80211: kernel reports: Error fetching BSS for link
wlp192s0: SME: Association request to the driver failed

During MLO roaming, the driver fails to provide BSS information for the target link.

3. Firmware State Machine Corruption

After the failed roaming sequence, firmware enters an unresponsive state:

  • Multiple MCU commands timeout (6+ second delays each)
  • Firmware stops processing command queue
  • Only recovery is firmware reset

Timeline Example

00:51:21 - Roaming triggered (6GHz target)
00:51:21 - MLO group key errors (3x)
00:51:21 - Key removal failed (-22)
00:51:22 - Authentication OK, Association FAILED
00:51:25 - AP requests comeback delay (SAE anti-clogging)
00:51:26 - Association timed out
00:51:29 - MCU timeout begins (firmware hung)
00:51:44 - Firmware reset triggered
00:51:51 - Reconnected to different BSSID
00:51:54 - Fully online

Mitigation Status

Issue Driver Fix Firmware Fix Needed
Key removal -EINVAL Patch 0012 No (driver bug)
BSS fetch failure NULL checks help Yes
MCU timeout recovery Patches prevent crash Root cause in FW
Firmware hang Auto-recovery works Shouldn't happen

What Our Patches Do

Without patches, this sequence would cause:

  • Kernel panic from NULL pointer dereference in VIF iteration
  • System deadlock from missing mutex in reset path
  • Hard reboot required

With patches:

  • Driver handles failures gracefully
  • Firmware reset completes successfully
  • Automatic reconnection works
  • Total downtime: ~30 seconds

For Users:

  • Apply patches from this repository
  • Use kernel 6.18+ with patches
  • Consider disabling 6GHz if roaming issues are frequent

For MediaTek/Upstream:

  1. Fix MLO group key handling in driver (mt7925_set_key())
  2. Investigate firmware state machine for roaming failures
  3. Add proper BSS info caching for MLO links
  4. Review MCU command queueing during rapid state transitions

Issue #2: Performance Degradation vs Intel Cards
Status Unmitigated (Firmware/Hardware)
Severity Medium

Summary

Users report significantly lower throughput compared to Intel WiFi cards in identical conditions.

Observed Performance

Card 5GHz Throughput Notes
Intel 8265 184-192 Mbit/s No MIMO
MT7925 18-26 Mbit/s With MIMO

Source: Framework Community benchmarks

Possible Causes

  • Firmware power management too aggressive
  • Driver rate control issues
  • Antenna configuration
  • MIMO not functioning correctly

Workarounds

None known. Some users have replaced the MT7925 with Intel AX210.

Issue #3: Frequent Deauthentication/Reauthentication Cycles
Status Partially Mitigated
Severity Low-Medium

Summary

The driver frequently disconnects and reconnects, especially in the first 1-2 hours after boot.

Symptoms

wlan0: deauthenticating from XX:XX:XX:XX:XX:XX by local choice (Reason: 3=DEAUTH_LEAVING)
wlan0: authenticate with XX:XX:XX:XX:XX:XX
wlan0: authenticated
wlan0: associated

This cycle repeats every few minutes.

Possible Causes

  • Aggressive roaming decisions
  • Power management state transitions
  • Regulatory domain changes triggering reconnection

Workarounds

Set regulatory domain explicitly:

# /etc/conf.d/wireless-regdom
WIRELESS_REGDOM="US"

Disable power management:

sudo iw dev wlan0 set power_save off

Reporting New Issues

If you encounter issues with the MT7925 driver:

  1. Capture dmesg output around the incident
  2. Note your kernel version and firmware version
  3. Check if our patches are applied: dkms status | grep mt76
  4. Open an issue on GitHub