Re: [Regression] TPM char device not created if TPM 1.2 is disabled, but visible

From: Jarkko Sakkinen
Date: Mon Mar 05 2018 - 07:14:56 EST


On Sat, Mar 03, 2018 at 09:27:36PM +0000, Sahil Rihan wrote:
> (Please CC me on replies - I'm not subscribed to LMKL)
>
> Prior to 0cf577a03f21 if a TPM 1.2 device was disabled, but visible (sysfs node "enabled" returns 0), creation of the TPM char device was only skipped if tpm_bios_log_setup returned -ENODEV.
>
> On some systems like HP DL380 G9, if the TPM is disabled but visible, the TCPA log is empty, which means tpm_read_log_acpi returns -EIO. Starting with 0cf577a03f21, -EIO triggers an early return from tpm_chip_register which means the char device is not created.
>
> Log snippet:
> [ 4.320387] tpm_tis 00:00: 1.2 TPM (device-id 0xB, rev-id 16)
> [ 4.455389] tpm tpm0: A TPM error (7) occurred attempting to read a pcr value
> [ 4.457762] tpm tpm0: TPM is disabled/deactivated (0x7)
> [ 4.459461] tpm tpm0: tpm_read_log_acpi: TCPA log area empty <----------------------
> [ 4.461312] tpm_tis: probe of 00:00 failed with error -5
>
> Thanks,
> Sahil

Thanks for the bug report, I appreciate it!

Personally I think we should keep the warning if the log area is empt
but tpm_read_log_acpi() should return -ENODEV in this case.

/Jarkko