Re: [tpmdd-devel] tpm device not showing up in /dev anymore

[Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>]

On Sat, Nov 11, 2017 at 12:46:47PM -0700, Jason Gunthorpe wrote:
> On Sat, Nov 11, 2017 at 12:12:57PM -0700, Jerry Snitselaar wrote:
> 
> > Before the release_locality code would only actually release the
> > locality if the request use bit was set. So after it grabbed the
> > locality during probe it probably never released it. The idea with the
> > new code was to release it when it was no longer needed so another
> > requester would be able to take the tpm without having to wait for it
> > to be released.
> 
> If I recall, this was so that system level things outside linux could
> access the TPM properly??
> 
> > With the old code I think it would have to wait either
> > until the next time release_locality was called, or attempt to seize
> > the tpm with the seize bit in the access register. I need to read
> > through the spec some more, but does the tpm ever force a change when
> > the request use bit is set, or does it leave it up to the software
> > to deal with it and only gets involved in the case where the seize
> > bit has been set?
> 
> Do we handle these cases? Maybe something like that has happened..
> 
> Jason

At least the driver works with TXT properly that uses locality 2.

The locality stuff for tpm_crb has bee made to work sanely with TXT.

/Jarkko