I've been running a some old-ish snapshot on Zyxel NBG6617 until 19.07rcx was released and everything seemed to be stable enough and very fast, every fast.com speed test while connected to 5Ghz was about my downlink speed(250Mbps)
After flashing both 19.07rc performance on 5Ghz Wifi(AC) has degraded so much that I get about only 20Mbps in speed tests and latency is all over the place(ssh to the router is a very very difficult). 2.4Ghz seems to work better, just the occasional hiccup.
On 5GHz I use 3 devices:
- one laptop with Marvel Avastar 802.11AC network card -> Wifi is not usable
- one phone with Qualcomm QCA 802.11AC wifi -> much better throughput in the speed test but latency is still very bad.
- one other laptop with bcm43xx network card 802.11AN wifi(wl driver) -> sometimes it can't even connect to WiFi 5Ghz
The current snapshot running 4.19 kernel has exactly the same problem.
Since I was sure at some point the wifi was fine I started bisecting the 19.07 branch for every kernel version bump.
The latest working and building commit has is 6ac1aa19579ddbee922ea5b89d7398f527baabd8:
kernel: bump 4.14 to 4.14.152
At the next bump with hash db345220b485ce3e20642bd1fbf9b65d5f1cd4f1
kernel: bump 4.14 to 4.14.155
I start experience the problems listed above.
Now between these 2 commits I see updates to mac80211, hostapd and wpad, and even a gcc bump. But there is quite a big number of commits and very time consuming to test each one, does anybody with more experience have any idea how I could narrow down the problem?
At this point 19.07 is not usable at all.