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scott_fakename

Member

Registered: 2012-08-15

Posts: 114

[solved] Unrealiable wifi, unless there's constant traffic

I have a ThinkPad L380 Yoga laptop which when I connect it to my 5ghz wifi, and then ping it from another device, I get frequent, extremely long packet delays and packet drops.

$ ping laptop 
PING laptop (192.168.1.206) 56(84) bytes of data.
64 bytes from laptop (192.168.1.206): icmp_seq=1 ttl=64 time=2914 ms
64 bytes from laptop (192.168.1.206): icmp_seq=24 ttl=64 time=4629 ms
64 bytes from laptop (192.168.1.206): icmp_seq=25 ttl=64 time=3605 ms
64 bytes from laptop (192.168.1.206): icmp_seq=26 ttl=64 time=2581 ms
64 bytes from laptop (192.168.1.206): icmp_seq=27 ttl=64 time=1558 ms
64 bytes from laptop (192.168.1.206): icmp_seq=28 ttl=64 time=534 ms
64 bytes from laptop (192.168.1.206): icmp_seq=32 ttl=64 time=1878 ms
64 bytes from laptop (192.168.1.206): icmp_seq=33 ttl=64 time=855 ms
64 bytes from laptop (192.168.1.206): icmp_seq=40 ttl=64 time=3612 ms
64 bytes from laptop (192.168.1.206): icmp_seq=41 ttl=64 time=2588 ms
64 bytes from laptop (192.168.1.206): icmp_seq=42 ttl=64 time=1564 ms
64 bytes from laptop (192.168.1.206): icmp_seq=43 ttl=64 time=541 ms
^C
--- laptop ping statistics ---
48 packets transmitted, 12 received, 75% packet loss, time 48140ms
rtt min/avg/max/mdev = 534.403/2238.304/4629.009/1255.420 ms, pipe 5

However, if I go on to the laptop itself and have it ping the router or an internet server, and then from another computer on the local network I ping the laptiop, I don't see long packet delays or drops, while the laptop is sending network traffic regularly as is the case during the time when the laptop is pinging the router or an internet server. When that's happening, traffic to the laptop over wifi is normal. But if I then stop the ping running on the laptop itself, the connection degrades again after some amount of time being idle.

I have tried changing a bunch of settings on the router, including changing the channel it broadcasts on, checking to see if the wifi is congested with other wifi base stations (it's not), and restarting the router, none of that has helped; This laptop is the only device that exhibits the issue, so I think the issue is the laptop itself.

According to the router, the laptop's signal doesn't seem weak, and the laptop has decent signal from the router too.

Any idea how I can debug this to find out what's going on?

Last edited by scott_fakename (2025-04-25 03:54:46)

-thc

Member

Registered: 2017-03-15

Posts: 998

Re: [solved] Unrealiable wifi, unless there's constant traffic

That behavior suspiciously sounds like a kind of power saving feature inside the WiFi chip (Intel 8265NGW) and driver (iwlwifi).
To my knowledge there are (kernel) driver module parameters to influence the power saving features on those chips.
I would try switching them.

scott_fakename

Member

Registered: 2012-08-15

Posts: 114

Re: [solved] Unrealiable wifi, unless there's constant traffic

It appears you're right; I have had this in my /etc/modprobe.d/iwlwifi.conf file for about a day and it seems to be working normally:

options iwlmvm power_scheme=1
options iwlwifi power_save=0