AcherC7 5Ghz wifi problems; and my X390 ethernet speed fuckup.

network-probloms-notes-22Jan20.md

Arher C7 5Ghz problems

好耐之前刷完Openwrt之後，config完一輪keep完用都冇乜事(雖然冇事但我都想換)
今朝搞咗陣個network試嘢改咗啲config之後
個5Ghz ac wifi就跪低咗 (Wireless is disabled or not associated to network)
轉咗做low freq嘅channel (channel 40) 先穩定用到
唯有係咁先。

Thinkpad X390 ethernet bugs on Linux

個driver冇問題 但default個ethernet config唔知做乜搞到bandwidth限咗100mbps
個fix:

sudo apt install ethtool
sudo ethtool -s enp0s31f6 speed 1000 duplex full autoneg off

Update

Permenant fix

sudo vim /etc/network/interfaces

# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback
pre-up /sbin/ethtool -s enp0s31f6 speed 1000 duplex full autoneg off   # add this line then save and reboot

注意有機會network-manager會set死咗Speed做100 Mbit/s, 如果係就要改，唔改嘅話喺/etc/network/interfaces config完都係會被nm改翻做100Mbps.

Cause: Dulpex mismatch / Problems with Auto-Negotiation

https://phoenixnap.com/kb/ethtool-command-change-speed-duplex-ethernet-card-linux