#11 hdparm -C Update to display EPC check power mode states

[David Okamoto]

Please add the following check power mode values (hdparm.c line 2513):
case 0x81: state = "idle_a"; break;
case 0x82: state = "idle_b"; break;
case 0x83: state = "idle_c"; break;

If a drive supports EPC (Identify device word 120, bit 7), and a set feature enables it, the check power mode output can be as shown in the attached image form ACS-6 draft spec.

If supported, this can issue a set feature to enable EPC:
sg_raw /dev/sdX a1 06 20 4a ff 04 00 00 a0 ef 00 00

and finally:
hdparm -C /dev/sdX

Example:
./hdparm -C /dev/sdc

/dev/sdc:
drive state is: idle_b

Thank you.