Re: [PATCH net-next v19 00/13] ax88179_178a: Add support for AX88179A-based chips

[Emir Beganovic <beganovic.emir@gmail.com>]

Hi Birger,

I tested v19 on a Dell DA305 USB-C adapter. It has an AX88179A
(0b95:1790, bcdDevice 0x0200, FW 1.0.7.131) behind a VIA VL822 hub,
plugged into a Dell XPS 16 (Panther Lake). The peer is an Intel I225-V
behind a switch.

I built ax88179, libphy, phylink and ax88796b as modules for a 7.2.8
kernel. v19 needed two things on that base: a4e22e9253e7 and a backport
of genphy_{read,write}_mmd_c45() from the adin1140 series.

With the current driver in configuration 1 this adapter never gets a
link ("Failed to read reg index 0x0040: -32"). With v19:

- 1000/full link with flow control
- download 940-941 Mbit/s in nine runs. Upload was 937-941 in five of
  nine and lower in the other four, and I couldn't find why. Eight
  later runs with tracing on all averaged about 932.
- 1-byte TCP request/response around 190-200 us, against about 1.46 ms
  with cdc_ncm on the same port (its default 400 us TX timer)
- switching itself to configuration 1 when the device comes up in the
  CDC configuration
- 100M and 10M links
- VLAN with rx-vlan-offload on and off, and rx-vlan-filter dropping a
  VID that isn't configured
- multicast filtering and allmulti
- suspend/resume (s2idle) and wake-on-LAN with a magic packet

Two small things I noticed:

- "Switching to vendor mode" is printed twice, once per CDC interface,
  and before the netdev is registered, so it shows up as
  "(unnamed net_device) (uninitialized)".
- After a WoL wake the link goes down and up twice within about 2.5 s,
  where a normal resume shows a single link up. It comes back fine
  either way.

I only have this one adapter, so nothing on the other chips.

Tested-by: Emir Beganovic <beganovic.emir@gmail.com>

Thanks,
Emir