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Comment by MiracleRabbit

2 days ago

The NICs need supported hardware timestamping. Then they can be used with ptp4l.

Intel i210 and i226 does this. But the i226 has a few variants.

> The NICs need supported hardware timestamping.

Yes. I'm aware. Perhaps I'm more stupid about this topic than normal, but it looks to me like the NICs I have do (NIC names have been changed for clarity, but all other output is untouched):

  $ ethtool -T intel-nic
  Time stamping parameters for intel-nic:
  Capabilities:
   hardware-transmit
   software-transmit
   hardware-receive
   software-receive
   software-system-clock
   hardware-raw-clock
  Hardware timestamp provider index: 0
  Hardware timestamp provider qualifier: Precise (IEEE 1588 quality)
  Hardware timestamp source: MAC
  Hardware Transmit Timestamp Modes:
   off
   on
  Hardware Receive Filter Modes:
   none
   all

  $ ethtool -T brcm-nic
  Time stamping parameters for brcm-nic:
  Capabilities:
   hardware-transmit
   software-transmit
   hardware-receive
   software-receive
   software-system-clock
   hardware-raw-clock
  Hardware timestamp provider index: 0
  Hardware timestamp provider qualifier: Precise (IEEE 1588 quality)
  Hardware timestamp source: MAC
  Hardware Transmit Timestamp Modes:
   off
   on
  Hardware Receive Filter Modes:
   none
   ptpv1-l4-event
   ptpv2-l4-event
   ptpv2-l2-event

  • Intel's drivers are notoriously annoying as the parent of the parent comment suggests. It seems to be a mix of hardware bugs and a driver that doesn't properly account for them. I know many who've moved to ASIX, Mellanox, and other chipsets just because they don't get weird behaviors or two edges per pulse without hacking the driver.

    • > It seems to be a mix of hardware bugs and a driver that doesn't properly account for them.

      ~~yaaaaay~~

      Also, who the heck knows if my switches are behaving correctly? I may be dealing with a system with multiple failing components.

      I'd never considered Mellanox hardware... I'd always thought of them as "super expensive datacenter hardware", but non-Infiniband cards I can see on Newegg aren't entirely-unreasonably priced. (TBD if I can find a PCI-E 2.0 1x card, though). I'd not heard of ASIX, and they have a card that would fit in my slot, but -sadly- no in-tree driver. It looks like the only in-tree driver is for a 100mbit card... the AX88796C.

      Anyway, thanks for the advice/info and the mention of more-reliable manufacturers.