tpm_clear requests that the system's TPM perform a clear (via the TPM_OwnerClear API) wiping out all ownership information, in effect invalidaing all keys and data tied to the TPM, as well as disabling and deactivating the TPM. This operation will prompt for the owner password. The --force option relies on Phyiscal Presence to authorize the command (via the TPM_ForceClear API) skipping the owner password prompt. The TPM OwnerClear API can be disabled until the current owner is cleared, requiring use of the --force with tpm_setclearable command. The TPM_ForceClear API can be disabled for the current boot cycle with the tpm_setclearable command. This command requires a reboot to complete the operation.
tpm_version(1) , tpm_takeownership(8) , tpm_setclearable(8) , tpm_setactive(8) , tpm_setenable(8) , tcsd(8)