Re: [PATCH v2 1/2] usb: uas: implement .change_queue_depth to allow per-device queue depth override

[Luca Cecchi <luca.cecchi.info@gmail.com>]

Hi Oliver, Alan,

Follow-up to yesterday's note. Good news: the test drive wasn't dying after all -
turned out to be heat/stress from several hours of back-to-back testing the day
before. After letting it rest, it's back to behaving exactly like it did during
our original Oct 4 testing.

Re-validated v3 on bare metal today, same Lexar ES3, same exact load test as
Oct 4 (24 sync writers, randwrite, 64KiB, direct=1, 360s each run):

- Confirmed the quirk applies on its own at probe time (queue_depth=24) even
  with the udev rule disabled, so it's not just masking a udev race.
- Two repeat runs of the original test: 840-843 MB/s, zero
  uas_eh_abort_handler/uas_eh_host_reset_handler events (matches the original
  822-823 MB/s baseline).
- Same test run concurrently with a second USB flash drive under load on the
  same controller: no effect on the Lexar's throughput or stability.
- Unplugged/replugged the Lexar mid-load: in-flight commands were cleaned up
  correctly (uas_zap_pending, no hang), device re-enumerated as SuperSpeed,
  uas re-bound, and the quirk re-applied queue_depth=24 on the new probe
  without any help from udev.
- Mixed read/write load (70/30): 614 MB/s read + 263 MB/s write, zero events.

Will send v3 shortly.

Luca