Hi just to say in the end i set in the hdparm.conf file to below. This drastically reduced the Temps (i have the full metal case for SATA HAT. and with out the power management it was reaching about 60c with all fans on full at idle. with it on i just have the top fan at 25% and its hardly warm to the touch.
If you can find a way to check what is supported, APM, spindown, acoustic (my drive does not support this) and then allow values to be set in the hat config switch it would be great.
I would also suggest having a global disable switch HDD power management some people might be using their own methods or services to manage it.
EDIT (If its part of the boot up script i suppose there is no need to edit the hdpram.conf file and just check what drives are attached to the ATAT HAT and run the commands. In this way of the HDD are swapped out or change there is no config file to clean up.
I used the direct mapping “/dev/sdb” but it would be better to use the serial numbers, and as i say cheek at each boot that its only the drives attached to the HAT it applies to.
/dev/sd[bcde] {
apm = 127
keep_features_over_reset = on
spindown_time = 242
}