> 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
Agree on keeping the warning. I'm guessing you want to return -ENODEV from tpm_bios_log_setup. Doing it from tpm_read_log_acpi will just fall through to calling tpm_read_log_of, which I think will end up returning -EIO again. In terms of semantics I'm not sure if -ENODEV is the right return code if the BIOS event log is absent. I guess you can claim it's some sort of "device". I don’t have a strong opinion here. Sahil
