25.12.1 Regression - packet delays

This device has worked perfectly up to and including 25.12.0. After a straightforward upgrade to 25.12.1 I am experiencing bursts of forwarding delays. I have had to revert to 25.12.0 and it is working well again.

Detail:

  • Ubiquiti UniFi 6 Lite
  • MediaTek MT7621 ver:1 eco:3
  • ramips/mt7621
  • SSID on 5g, 802.11r enabled (FT over the Air), in conjunction with a Unifi 6 Plus device
  • Raspberry Pi 3b media server near the Lite, connected to the 5g radio
  • Zabbix ping polling the Pi every minute over the wired ethernet

Symptoms:

  • Zabbix showing no ping response for anything from 1-15 minutes
  • Pinging the Pi from a workstation over wired ethernet shows no response for a few packets, then all replies arrive in quick succession, then it settles down.
  • Stop the ping for a few seconds, then start and the delayed-first-responses repeats.
  • I don't know whether the ping requests or responses are being delayed
  • Pi remains associated with the Lite, and does not fail over to the Plus
  • Nothing of interest in the Lite logs, in particular nothing related to the Pi MAC
  • A pair of crond log entries every minute (wakeup dt=60, file root:) which I presume are benign and weren't there in 25.12.0

Ideas (probably mostly wrong):

  • Something to do with wlan power management?
  • I saw something about scheduler changes?

I don't know whether this is specific to the chipset, the target, or wider. I would have to wait until a day when noone else is here to do any more experimenting but happy to do so if needed.

Thanks, Chris

There has been a problem with the MT7915 wifi in the latest release. See the post below. It has been fixed but you will need to switch to snapshot or wait for the next release.

2 Likes

Ok. Thank you so much for the fast reply!

Chris

Maybe add this to the known issues list? It’s not on it at the moment.