Gigabit Ethernet only in 100MB/s Mode

grininmonkey · 2021-01-04 04:08:11

# lspci | grep Ethernet
02:00.0 Ethernet controller: Qualcomm Atheros Killer E2400 Gigabit Ethernet Controller (rev 10)

# dmesg | grep enp2s0
[    5.829055] alx 0000:02:00.0 enp2s0: renamed from eth0
[   17.818452] alx 0000:02:00.0 enp2s0: NIC Up: 100 Mbps Full

# ethtool enp2s0
Settings for enp2s0:
	Supported ports: [ TP ]
	Supported link modes:   10baseT/Half 10baseT/Full
	                        100baseT/Half 100baseT/Full
	                        1000baseT/Full
	Supported pause frame use: Symmetric Receive-only
	Supports auto-negotiation: Yes
	Supported FEC modes: Not reported
	Advertised link modes:  10baseT/Half 10baseT/Full
	                        100baseT/Half 100baseT/Full
	                        1000baseT/Full
	Advertised pause frame use: Symmetric
	Advertised auto-negotiation: Yes
	Advertised FEC modes: Not reported
	Speed: 100Mb/s
	Duplex: Full
	Auto-negotiation: on
	Port: Twisted Pair
	PHYAD: 0
	Transceiver: internal
	MDI-X: Unknown
        Current message level: 0x000060e4 (24804)
                               link ifup rx_err tx_err hw wol
	Link detected: yes

I tried swaping patch cables with another box off same switch, same cable works fine for other box in full 1000Mb/s but not the box with my issue so I can rule out faulty cable.

When I try to manually set it... it get the following...

# ethtool -s enp2s0 speed 1000 duplex full
netlink error: link settings update failed
netlink error: Invalid argument

Its a dumb switch, and I power cycled, etc... 4 other boxes are in 1000Mb/s mode just fine off the switch so... I am a bit stumped with this one...

seth · 2021-01-04 09:09:23

Auto-negotiation: on

First ensure to bring the NIC down, then try

# ethtool -s enp2s0 autoneg offf speed 1000 duplex full

grininmonkey · 2021-01-04 12:50:41

I tried that via this first....

ip link set dev enp2s0 down

Then attempting any form / combination of ethtool -s results in the same message

# ethtool -s enp2s0 speed 1000 duplex full autoneg off
netlink error: link settings update failed
netlink error: Invalid argument

....

# ethtool -s enp2s0 speed 10 duplex full autoneg off
netlink error: link settings update failed
netlink error: Invalid argument

I also tried creating a NetworkManager system-connections for the named connection... which seems to have "NO" effect as well...

[connection]
id=Wired connection 1
uuid=4462661f-a2b5-3105-bd77-2d06938f770d
type=ethernet
autoconnect-priority=-999
interface-name=enp2s0
permissions=
timestamp=1609735993

[ethernet]
auto-negotiate=false
duplex=full
speed=1000
mac-address-blacklist=

[ipv4]
dns-search=
method=auto

[ipv6]
addr-gen-mode=stable-privacy
dns-search=
method=auto

seth · 2021-01-04 13:40:24

creating a NetworkManager system-connections

If NM is still running, attempts to bring the NIC down will likely fail.
=> First stop NM and ensure no other NIC controlling service is running - in doubt post the output of

find /etc/systemd -type l -exec test -f {} \; -print | awk -F'/' '{ printf ("%-40s | %s\n", $(NF-0), $(NF-1)) }' | sort -f

to list enabled ones

grininmonkey · 2021-01-04 14:33:51

I disabled NetworkManager, rebooted and captured the following outputs

# dmesg | grep enp2s0
[    5.596209] alx 0000:02:00.0 enp2s0: renamed from eth0

# find /etc/systemd -type l -exec test -f {} \; -print | awk -F'/' '{ printf ("%-40s | %s\n", $(NF-0), $(NF-1)) }' | sort -f
dirmngr.socket                           | sockets.target.wants
getty@tty1.service                       | getty.target.wants
gpg-agent-browser.socket                 | sockets.target.wants
gpg-agent-extra.socket                   | sockets.target.wants
gpg-agent.socket                         | sockets.target.wants
gpg-agent-ssh.socket                     | sockets.target.wants
mssql-server.service                     | multi-user.target.wants
nginx.service                            | multi-user.target.wants
p11-kit-server.socket                    | sockets.target.wants
php-fpm.service                          | multi-user.target.wants
remote-fs.target                         | multi-user.target.wants
smb.service                              | multi-user.target.wants
sshd.service                             | multi-user.target.wants
wsdd.service                             | multi-user.target.wants

# ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp2s0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether d8:cb:8a:9f:46:7a brd ff:ff:ff:ff:ff:ff

# ethtool -s enp2s0 speed 1000 duplex full autoneg off
netlink error: link settings update failed
netlink error: Invalid argument

seth · 2021-01-04 14:45:33

Didn't completely read the thread, but seems related, https://www.mail-archive.com/netdev@vge … 58204.html

Did you try the lts kernel?

grininmonkey · 2021-01-04 14:58:03

have not tried lts... but another odd behavior I am getting is that I realized by accident when I logged in via a sudoer account vs root.... ethtool -s seems to work as long as I do not specify speed 1000... meaning I can sudo ethtool -s enp2s0 speed 10 duplex full autoneg off etc... but gets the error if I try to specify speed 1000...

But when logged in as root at tty1... ethtool returns the invalid argument "period" no matter what.

grininmonkey · 2021-01-04 15:16:38

I installed lts and get the same end result, however the error response from ethtool/netlink is formatted differently ...

# ethtool -s enp2s0 speed 1000 duplex full autoneg off
Cannot set new settings: Invalid argument
   not setting speed
   not setting duplex
   not setting autoneg

under lts.... I also tried this

# ethtool -s enp2s0 speed 1000 
Cannot advertise speed 1000
Cannot set new settings: Invalid argument
  not setting speed

better verbose under lts.... anyway.....

Last edited by grininmonkey (2021-01-04 15:27:52)

grininmonkey · 2021-01-04 15:55:11

Ok... I am both happy and puzzled...

Settings for enp2s0:
	Supported ports: [ TP ]
	Supported link modes:   10baseT/Half 10baseT/Full 
	                        100baseT/Half 100baseT/Full 
	                        1000baseT/Full 
	Supported pause frame use: Symmetric Receive-only
	Supports auto-negotiation: Yes
	Supported FEC modes: Not reported
	Advertised link modes:  10baseT/Half 10baseT/Full 
	                        100baseT/Half 100baseT/Full 
	                        1000baseT/Full 
	Advertised pause frame use: Symmetric
	Advertised auto-negotiation: Yes
	Advertised FEC modes: Not reported
	Speed: 1000Mb/s
	Duplex: Full
	Port: Twisted Pair
	PHYAD: 0
	Transceiver: internal
	Auto-negotiation: on
	MDI-X: Unknown
	Current message level: 0x000060e4 (24804)
			       link ifup rx_err tx_err hw wol
	Link detected: yes

I repeated the following with consistent results and I don't understand it.... my only assumption is that the NIC on the MB is simply a cable snob of some sorts and is extremely picky.

I have 5 devices with 1G nics plugged into my dumb switch... all using 6ft 5e patch cables. 4 ( original ) have had no issue linking at 1000, never once messed with this. The new box is a repurpose older MB/CPU that I originally ran Arch on more than a year ago before new hardware... just dusted it off and decided to do something with it...

So anyway... I was unplugging from my main computer and plugging that cable into this box with this issue and same with others... after just trying lts I thought... hey.. I do have a Cat6 cable... let me try for giggles and why not.... [ pow ] it linked @ 1000... so I then decided to reboot into mainline kernel... [ rut row ] will only link @ 100 with new Cat6 cable... reboot into lts and it links @ 1000 with Cat6 cable.... plug in any of the other 4 in use and working fine @ 1000 Cat5e cables... and nope.. only links @ 100...

This is the oddest network experience I have had so far.... its a 2016 MB i7 6700K and going to be a dev LEMP box.. so LTS is fine... but very weird none the less..

Last edited by grininmonkey (2021-01-04 16:01:05)

Arch Linux

#1 2021-01-04 04:08:11

Gigabit Ethernet only in 100MB/s Mode

#2 2021-01-04 09:09:23

Re: Gigabit Ethernet only in 100MB/s Mode

#3 2021-01-04 12:50:41

Re: Gigabit Ethernet only in 100MB/s Mode

#4 2021-01-04 13:40:24

Re: Gigabit Ethernet only in 100MB/s Mode

#5 2021-01-04 14:33:51

Re: Gigabit Ethernet only in 100MB/s Mode

#6 2021-01-04 14:45:33

Re: Gigabit Ethernet only in 100MB/s Mode

#7 2021-01-04 14:58:03

Re: Gigabit Ethernet only in 100MB/s Mode

#8 2021-01-04 15:16:38

Re: Gigabit Ethernet only in 100MB/s Mode

#9 2021-01-04 15:55:11

Re: Gigabit Ethernet only in 100MB/s Mode

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