Re: [tpmdd-devel] [PATCH] tpm: Add sysfs interface to show TPM hardware version

[James Bottomley]

On Tue, 2017-03-14 at 15:24 -0600, Jason Gunthorpe wrote:
> On Tue, Mar 14, 2017 at 07:58:37PM +0100, Peter Huewe wrote:
> 
> > > In practice, I suspect that a single user space application won't
> > > support both TPMs. 
> > Think of init scripts.
> > Which daemon should it start?
> 
> Right, ideally we'd have a udev rule that triggers systemd to start
> the userspace daemons when a TPM is detected, as other hardware does.
> 
> So whatever format we use has to be compatible with udev's matcher..

Technically, we have that already: my TPM2.0 detection stuff for udev
triggers off the presence of the SUBSYSTEM=="tpmrm"  that matches any
TPM2 device but not a 1.x one.

James