SUMMARY

Since the internal SSD only has some GB, I also use an external (mechanical) HDD with some TB for storage connected via USB-SATA adapter. This HDD shouldn't be powered all the time, but only for the few minutes per day I need it.

My previous workflow:
  1. click disk in Device Notifier to mount it (it automatically powered up)
  2. copy stuff to archive/backup from SD to HDD
  3. click "unmount" icon in Device Notifier to unmount it
  4. wait a few seconds until mechanics settles
  5. issue a "hdparm -y /dev/sdX" as root to power down
  6. repeat with step 1 any time later

Newer versions of the Device Notifier aimed to improve the workflow by automatically powering down. Unfortunately, there are regressions as described below.

STEPS TO REPRODUCE
  1. click on external disk in Device Notifier to mount it, then optionally use it
  2. click on unmount/safely remove icon in Device Notifier
  3. external disk abruptly powers down
  4. open Device Notifier again and try to mount the disk again

OBSERVED RESULT
  1. The external disk is no longer listed in the Device Notifier. I have to walk around the table to disconnect and reconnect the disk. Since SATA plugs cannot be removed without some wiggling when pulling, I fear that I soon break the SATA connector on the HDD, and never be able to access the disk again.
  2. Power-down noise is different (and sounds unhealthy) compared to previous workflow

EXPECTED RESULT
  1. The device is still listed in the Device Notifier (because it is still connected) to be able to mount it again.
  2. The device is powered down in the same way the 'hdparm -y' call did, ideally with a few seconds delay to settle down the mechanics.

SOFTWARE/OS VERSIONS
- Plasma: master (unreleased 5.15.60)
- KF5: master (unreleased 5.57.0)
- Qt5: 5.12.2