On 02/09/2018 03:32 PM, Jarkko Sakkinen wrote:
On Thu, Feb 08, 2018 at 09:02:00AM -0800, James Bottomley wrote:
There is an identified regression: the TPM driver will now periodically
fail to attach. However, there's no point reviewing until we agree
what the fix is. I was just waiting to verify this fixed my problem
(which means seeing the messages it spits out proving the TPM has
remained in self test). I have now seen this and the driver still
works, so I can submit a formal patch.
For the self-test the duration falls down to 2 seconds as the specs do
not contain any well-defined duration for it, or at least I haven't
found it.
I see three alternative ways the fix the self-test:
1. Execute self-test with fullTest = YES.
2. Have a flag TPM_CHIP_TESTING that is set when the self-test is
started. Issue a warning on time-out. Check for this flag in
tpm_transmit_cmd() and tpm_write() and resend self-test command
if the flag is stil test before the actual command. Return -EBUSY
and print a warning if self-test is still active.
3. Increase the duration to the "correct" value if we have one.
/Jarkko
IIUC, I see the duration and timeout specified in
TCG_PC_Client_Platform_TPM_Profile_PTP_Specification_Family_2.0_Revision:
Section 5.5.1.3 Command Timing: Table 15
For selftest it is given as:
Command | Duration[ms] |
Timeout[ms]
TPM2_SelfTest(fullTest=YES) 1000 2000
TPM2_SelfTest(fullTest=NO) 20 750
With that I think, TPM is expected to complete the selftest in max 2000 ms.
Thanks & Regards,
- Nayna
