Re: tpm device not showing up in /dev anymore - Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w

From: <Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org>
To: bigon-8fiUuRrzOP0dnm+yROfE0A@public.gmane.org,
	jsnitsel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org
Cc: tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Subject: Re: tpm device not showing up in /dev anymore
Date: Thu, 31 Aug 2017 12:10:46 +0000	[thread overview]
Message-ID: <857106e4bb864bb8a68b1381fffc8f50@MUCSE603.infineon.com> (raw)
In-Reply-To: <595efb25-8d87-f39d-037f-9c9a98462339-8fiUuRrzOP0dnm+yROfE0A@public.gmane.org>

> Le 29/08/17 à 18:35, Laurent Bigonville a écrit :
> > Le 29/08/17 à 18:00, Alexander.Steffen@infineon.com a écrit :
> >>> An idea how to troubleshoot this?
> >> Can you run git bisect on the changes between 4.11 and 4.12, so that
> >> we find the offending commit? It is probably sufficient to limit the
> >> search to commits that touch something in drivers/char/tpm.
> >
> > I'll try and keep you posted.
> 
> OK I've been able to bisect the problem and the bad commit is:
> 
> e6aef069b6e97790cb127d5eeb86ae9ff0b7b0e3 is the first bad commit
> commit e6aef069b6e97790cb127d5eeb86ae9ff0b7b0e3
> Author: Jerry Snitselaar <jsnitsel@redhat.com>
> Date:   Mon Mar 27 08:46:04 2017 -0700
> 
>      tpm_tis: convert to using locality callbacks
> 
>      This patch converts tpm_tis to use of the new tpm class ops
>      request_locality, and relinquish_locality.
> 
>      With the move to using the callbacks, release_locality is changed so
>      that we now release the locality even if there is no request pending.
> 
>      This required some changes to the tpm_tis_core_init code path to
>      make sure locality is requested when needed:
> 
>        - tpm2_probe code path will end up calling request/release through
>          callbacks, so request_locality prior to tpm2_probe not needed.
> 
>        - probe_itpm makes calls to tpm_tis_send_data which no longer calls
>          request_locality, so add request_locality prior to tpm_tis_send_data
>          calls. Also drop release_locality call in middleof probe_itpm, and
>          keep locality until release_locality called at end of probe_itpm.
> 
>      Cc: Peter Huewe <peterhuewe@gmx.de>
>      Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
>      Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
>      Cc: Marcel Selhorst <tpmdd@selhorst.net>
>      Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
>      Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
>      Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
>      Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> 
> :040000 040000 70234365da69959d47076ebb40c8d17f520c3e44
> 72f21b446e45ea1003de75902b0553deb99157fd M	drivers
> 

I've looked again at the code in question, but could not find anything that is obviously wrong there. Locality is now requested/released at slightly different points in the process than before, but that's it. It does not seem to cause problems with the majority of TPMs, since you are the first to report any, so maybe it is a quirk that only affects this device.

Perhaps Jerry can help, since this is his change?

Alexander
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