I have an ASUS Pro WS X570-ACE motherboard, with AMD Ryzen 5700G, with on-board Intel I211 Ethernet, running driver igb ver. 5.11.0-27. This also has a Realtek onboard Ethernet, but that is disabled in BIOS. The OS is Linux Mint 20.2 running kernel 5.11.0-27-generic.
Whenever the OS boots up, the following is shown in 'dmesg' output:
pps_core: LinuxPPS API ver. 1 registered
pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <[email protected]>
pps pps0: new PPS source ptp0
pps_ldisc: PPS line discipline registered
And 2 devices show up: /dev/pps0 and /dev/ptp0
I know that it is the Intel I211 port that is doing this because if I run ethtool -T enp5s0 on the adapter, it says:
Time stamping parameters for enp5s0:
Capabilities:
hardware-transmit (SOF_TIMESTAMPING_TX_HARDWARE)
software-transmit (SOF_TIMESTAMPING_TX_SOFTWARE)
hardware-receive (SOF_TIMESTAMPING_RX_HARDWARE)
software-receive (SOF_TIMESTAMPING_RX_SOFTWARE)
software-system-clock (SOF_TIMESTAMPING_SOFTWARE)
hardware-raw-clock (SOF_TIMESTAMPING_RAW_HARDWARE)
PTP Hardware Clock: 0
Hardware Transmit Timestamp Modes:
off (HWTSTAMP_TX_OFF)
on (HWTSTAMP_TX_ON)
Hardware Receive Filter Modes:
none (HWTSTAMP_FILTER_NONE)
all (HWTSTAMP_FILTER_ALL)
The PTP Hardware Clock: 0 means that this creates the /dev/ptp0 and thus /dev/pps0. Here is a list of relevant devices in /dev/:
/dev/port /dev/ppp /dev/pps0 /dev/pps1 /dev/psaux /dev/ptmx /dev/ptp0 /dev/ptp1 /dev/ptp2
The reason why this PTP is a problem for me is because I use a GPS receiver to set time.
I have a GPS receiver connected via the onboard COM/Serial DB9 connector, which I use to set the time on the computer to micro-second precision using the Pulse Per Second (PPS) coming in onto Pin 1 over the serial. GPSD and CHRONY take care of the rest...but the problem is that GPSD creates its PPS device at /dev/pps1, rather than /dev/pps0 due to the PTP. GPSD normally expects its PPS source to be /dev/pps0. GPSD does work if I specify in the command line to refer to /dev/pps1 as the PPS source...but it takes several more minutes to lock and sync versus a computer that has no PTP at all...
pps_core: LinuxPPS API ver. 1 registered
pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <[email protected]>
pps pps0: new PPS source ptp0
pps_ldisc: PPS line discipline registered
pps pps1: new PPS source serial0
pps pps1: source "/dev/ttyS0" added
I looked at the Ethtool manual and Intel IGB driver build guide, but there is no parameter that can be set to turn off HARDWARE_TIMESTAMPS. Ethtool only has the -T switch, that shows the timestamping capability...but no actual options you can set via ethtool -T/-t.
Question: Is there a way for me to completely disable this PTP system entirely ?