Update for posterity-
Mellanox support provided a work-around of using mlxcables instead of
ethtool to read alarm/warning info for an installed transceiver.
I was told that a couple of their engineers are currently looking into the
discrepancy between threshold reporting by mlxcables and ethtool, and
that they are deciding what to do about it...
Work-around steps:
1. add a cable with "sudo mst cable add".
2. find the cable name with "sudo mlxcables". The name of my cable is
01:00.0_cable_0 so I copy that name for insertion into the next command.
3. probe the cable for DDM with "sudo mlxcables -d 01:00.0_cable_0 --DDM".
Example copied/pasted from my CLI here.
All reported thresholds appear to be correct.
tech1@D7:~$
tech1@D7:~$
tech1@D7:~$ sudo mst cable add
-I- Added 1 cable devices ..
tech1@D7:~$ sudo mlxcables
Querying Cables ....
Cable #1:
---------
Cable name : 01:00.0_cable_0
>> No FW data to show
-------- Cable EEPROM --------
Identifier : QSFP28 (11h)
Technology : 850 nm VCSEL (00h)
Compliance : Extended Specification Compliance is valid, 100GBASE-SR4 or
25GBASE-SR
Wavelength : 850 nm
OUI : 0x00c0f2
Vendor : TRANSITION
Serial number : TN02000263
Part number : TN-QSFP-100G-SR4
Revision : 02
Temperature : 34 C
Length : 50 m
tech1@D7:~$ sudo mlxcables -d 01:00.0_cable_0 --DDM
Cable DDM:
----------
Temperature : 34C
Voltage : 3.2918V
Channel 1:
RX Power : 0.1695dBm
TX Power : 0.8622dBm
TX Bias : 7.0720mA
Channel 2:
RX Power : 0.1355dBm
TX Power : 1.1042dBm
TX Bias : 6.9240mA
Channel 3:
RX Power : -0.1592dBm
TX Power : 0.6547dBm
TX Bias : 6.9420mA
Channel 4:
RX Power : -0.1300dBm
TX Power : 0.4653dBm
TX Bias : 6.9120mA
----- Thresholds -----
Temperature:
High Warning : 70C
Low Warning : 0C
High Alarm : 75C
Low Alarm : -5C
Warning mask : 0
Alarm mask : 0
Voltage:
High Warning : 3.4600V
Low Warning : 3.1300V
High Alarm : 3.6300V
Low Alarm : 2.9700V
Warning mask : 0
Alarm mask : 0
Channel 1:
RX Power high warn : 2.4000dBm
RX Power low warn : -9.5001dBm
RX Power high alarm : 5.4103dBm
RX Power low alarm : -12.5104dBm
RX Power Warning mask: 0
RX Power Alarm mask : 0
TX Power high warn : 2.4000dBm
TX Power low warn : -7.6020dBm
TX Power high alarm : 3.1917dBm
TX Power low alarm : -8.5699dBm
TX Power Warning mask: 0
TX Power Alarm mask : 0
TX Bias high warn : 12.0000mA
TX Bias low warn : 2.0000mA
TX Bias high alarm : 15.0000mA
TX Bias low alarm : 1.0000mA
TX Bias Warning mask : 0
TX Bias Alarm mask : 0
Channel 2:
RX Power high warn : 2.4000dBm
RX Power low warn : -9.5001dBm
RX Power high alarm : 5.4103dBm
RX Power low alarm : -12.5104dBm
RX Power Warning mask: 0
RX Power Alarm mask : 0
TX Power high warn : 2.4000dBm
TX Power low warn : -7.6020dBm
TX Power high alarm : 3.1917dBm
TX Power low alarm : -8.5699dBm
TX Power Warning mask: 0
TX Power Alarm mask : 0
TX Bias high warn : 12.0000mA
TX Bias low warn : 2.0000mA
TX Bias high alarm : 15.0000mA
TX Bias low alarm : 1.0000mA
TX Bias Warning mask : 0
TX Bias Alarm mask : 0
Channel 3:
RX Power high warn : 2.4000dBm
RX Power low warn : -9.5001dBm
RX Power high alarm : 5.4103dBm
RX Power low alarm : -12.5104dBm
RX Power Warning mask: 0
RX Power Alarm mask : 0
TX Power high warn : 2.4000dBm
TX Power low warn : -7.6020dBm
TX Power high alarm : 3.1917dBm
TX Power low alarm : -8.5699dBm
TX Power Warning mask: 0
TX Power Alarm mask : 0
TX Bias high warn : 12.0000mA
TX Bias low warn : 2.0000mA
TX Bias high alarm : 15.0000mA
TX Bias low alarm : 1.0000mA
TX Bias Warning mask : 0
TX Bias Alarm mask : 0
Channel 4:
RX Power high warn : 2.4000dBm
RX Power low warn : -9.5001dBm
RX Power high alarm : 5.4103dBm
RX Power low alarm : -12.5104dBm
RX Power Warning mask: 0
RX Power Alarm mask : 0
TX Power high warn : 2.4000dBm
TX Power low warn : -7.6020dBm
TX Power high alarm : 3.1917dBm
TX Power low alarm : -8.5699dBm
TX Power Warning mask: 0
TX Power Alarm mask : 0
TX Bias high warn : 12.0000mA
TX Bias low warn : 2.0000mA
TX Bias high alarm : 15.0000mA
TX Bias low alarm : 1.0000mA
TX Bias Warning mask : 0
TX Bias Alarm mask : 0
tech1@D7:~$
tech1@D7:~$
tech1@D7:~$
Chris Preimesberger
