Re: [PATCH] accel/rocket: clear rdev on device init failure

[Igor Paunovic <royalnet026@gmail.com>]

Hi Guangshuo,

I have been working on this driver on RK3588 (Orange Pi 5 Plus) and
went through your fix carefully:

- The analysis matches the code: rocket_probe() publishes the ERR_PTR
  into the file-scoped rdev before the IS_ERR() check, and since
  __driver_attach() keeps probing the remaining devices after a failed
  probe, the next rknn-core dereferences the poisoned pointer at
  rdev->num_cores. Every RK3588 DT carries three rknn-core nodes, so
  the follow-up probe is guaranteed.

- rocket_device_init() cannot return -EPROBE_DEFER (it does no clock,
  regulator or supplier lookups), so clearing rdev here cannot
  interfere with the deferral path in rocket_core_init(), which
  already resets rdev correctly further down in rocket_probe().

- The fix mirrors the shape the driver already uses on the
  rocket_core_init() failure path (fini + rdev = NULL) and changes
  nothing on the success path.

Reviewed-by: Igor Paunovic <royalnet026@gmail.com>

I also ran the patched driver on RK3588: normal three-core probe,
runtime PM suspend/resume and a Teflon/MobileNetV1 inference run are
all unaffected.

Thanks,
Igor