A correction to the Tested section: "other firmware" is wrong. The
card keeps its operating mode in the high byte of bcdDevice -- 01xx
Mobile, 02xx Live Streaming, 03xx Pro Audio -- so the second card's
1.45 is Mobile Mode, against Pro Audio Mode (3.27) on the first.

That also covers the one item the letter lists as not re-run for v8,
Mobile Mode without a UCM profile. The second card ran in Mobile Mode
throughout: its nine controls were created, it bound again in each of
the fifty reload cycles, its own knob reported to its own card after
the second suspend while the first card's knob left it alone before
and after, and its cable pull ended in a clean rebind.

Two items from the "Not tested" list have been run since, on the
first card, each time with all three of its snd-usb-audio interfaces
unbound and the control interface bound again:

  - with the HID driver left bound: the component bound again on the
    new card at once, all nineteen controls were back, and the
    headphone volume was as before the unbind;
  - with hid-topping unloaded first and loaded after the card had
    registered: both components bound at the load, and the nine
    controls appeared on the registered card. They start from the
    driver's defaults, the headphone volume at 0: the restorers act
    when the card appears, before these controls exist, so "alsactl
    restore" has to be run again, and it brings the saved values
    back.

No WARNING, BUG, KASAN, UBSAN, lockdep report or call trace in the
kernel log over these runs.

-- 
Thanks,
Mikhail.