From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f179.google.com ([209.85.223.179]:44618 "EHLO mail-io0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751810AbdKKTqt (ORCPT ); Sat, 11 Nov 2017 14:46:49 -0500 Received: by mail-io0-f179.google.com with SMTP id m16so16855688iod.1 for ; Sat, 11 Nov 2017 11:46:49 -0800 (PST) Date: Sat, 11 Nov 2017 12:46:47 -0700 From: Jason Gunthorpe To: Jerry Snitselaar Cc: Laurent Bigonville , Jarkko Sakkinen , Alexander.Steffen@infineon.com, linux-integrity@vger.kernel.org Subject: Re: [tpmdd-devel] tpm device not showing up in /dev anymore Message-ID: <20171111194647.GA6918@ziepe.ca> References: <20171024145706.na56ff34w5agzo2t@rhwork> <20171024160725.r6kj452jdzpkbb6o@linux.intel.com> <8f4df9a9-c8cd-832f-4c3f-5305fabab7a8@debian.org> <0a6e4771-f871-b3ca-b5b0-26dbd9efa8b1@debian.org> <20171110002820.wtfvb3tv5fcjqecu@localhost.localdomain> <20171110070738.ki5xie4z7yql77fk@localhost.localdomain> <9245ef7d-dd34-fa5f-6fd9-bfb9582f910e@debian.org> <20171110205300.eyfkoyabobv7llgb@localhost.localdomain> <20171111154516.GI17451@ziepe.ca> <20171111191257.owuqtgzie3ostsab@cantor> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20171111191257.owuqtgzie3ostsab@cantor> Sender: linux-integrity-owner@vger.kernel.org List-ID: 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