SOLVED: Force use of engine all the time

Kenneth Goldman kgoldman at
Thu Nov 7 16:04:20 UTC 2019

From:	Frederick Gotham <cauldwell.thomas at>
To:	openssl-users at
Date:	11/07/2019 10:39 AM
Subject:	[EXTERNAL] Re: SOLVED: Force use of engine all the time
Sent by:	"openssl-users" <openssl-users-bounces at>

Frederick Gotham wrote:

> I don't think any code other than "" is using the TPM2, and
> I don't know why I'm getting "device or resource busy" (considering I'm
> using a global named mutex)". I see that there's also a TPM2 tcti called
> "abrmd", and I'm not sure if this purpose is exactly what it's for.

Just FYI, abrmd was a TPM 2.0 user space resource manager, similar to the
TPM 1.2 tcsd.  Recent Linux kernels have a kernel driver resource manager
at /dev/tpmrm0 that removes the need for a user space daemon.

/dev/tpmrm0 supports multiple opens and does the swapping and
scheduling.  /dev/tpm0 is the original single open entry point, and
would not normally be used.

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