How to send "ATA Secure Erase" command to SSD?

Here are the steps:

1. See if the feature is not frozen. hdparm -I /dev/sdX. If it is (usually by the BIOS), a good way to unfreeze it is to suspend the computer, and resume - then the drive gets powered up, but without BIOS.
2. IMPORTANT: set the password. This will enable the security feature of the drive: hdparm --user-master u --security-set-pass password /dev/sdX
3. Lastly, erase the drive:hdparm --user-master u --security-erase password /dev/sdX

The procedure is described here in more detail: https://wiki.archlinux.org/index.php/SSD_memory_cell_clearing

Example from my drive:

Security: 
    Master password revision code = 65534
        supported
    not enabled
    not locked
        frozen
    not expired: security count
    not supported: enhanced erase
    2min for SECURITY ERASE UNIT.

So it is frozen... now I suspend... and...

Security: 
    Master password revision code = 65534
        supported
    not enabled
    not locked
    not frozen
    not expired: security count
    not supported: enhanced erase
    2min for SECURITY ERASE UNIT.