Trying to change the AAM to another level for the ST910021AS leads to the following error.
I trey the values 0, 128, 256
All with the same output.
# hdparm -M 128 /dev/sda
setting acoustic management to 128
HDIO_DRIVE_CMD:ACOUSTIC failed: Input/output error
HDIO_DRIVE_CMD(identify) failed: Input/output error
I attached the output of hdparm -I
Let me know if you need further information