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Subject: Re: [PATCH v4 3/7] tpm: tpm_tis: rewrite "tpm_tis_req_canceled()"
To:     Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        amirmizi6@gmail.com
Cc:     Eyal.Cohen@nuvoton.com, oshrialkoby85@gmail.com,
        alexander.steffen@infineon.com, robh+dt@kernel.org,
        mark.rutland@arm.com, peterhuewe@gmx.de, jgg@ziepe.ca,
        arnd@arndb.de, gregkh@linuxfoundation.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-integrity@vger.kernel.org, oshri.alkoby@nuvoton.com,
        tmaimon77@gmail.com, gcwilson@us.ibm.com, kgoldman@us.ibm.com,
        Dan.Morav@nuvoton.com, oren.tanami@nuvoton.com,
        shmulik.hager@nuvoton.com, amir.mizinski@nuvoton.com
References: <20200331113207.107080-1-amirmizi6@gmail.com>
 <20200331113207.107080-4-amirmizi6@gmail.com>
 <20200331121352.GA9284@linux.intel.com>
From:   Ken Goldman <kgold@linux.ibm.com>
Message-ID: <774fa2af-e4a6-4577-f1f7-c786e3b5210c@linux.ibm.com>
Date:   Tue, 31 Mar 2020 09:52:15 -0400
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On 3/31/2020 8:13 AM, Jarkko Sakkinen wrote:
> On Tue, Mar 31, 2020 at 02:32:03PM +0300, amirmizi6@gmail.com wrote:
>> From: Amir Mizinski <amirmizi6@gmail.com>
>>
>> Using this function while read/write data resulted in aborted operation.
>> After investigating according to TCG TPM Profile (PTP) Specifications,
>> i found cancel should happen only if TPM_STS.commandReady bit is lit and
>> couldn't find a case when the current condition is valid.
>> Also only cmdReady bit need to be compared instead of the full lower status
>> register byte.
>>
>> Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
> 
> We don't care about spec's. We care about hardware and not all hardware
> follows specifications.
> 
> Please fix the exact thing you want to fix (and please provide a fixes
> tag).

I edit the TPM main spec, not the PTP.  As I discover TPMs that don't 
meet the spec, or where the spec has changed over time, I add 
informative comments to guide developers.

If you know of TPM hardware that does not meet the PTP specification, 
let me know the specifics.  I can bring it to the PTP work group and try 
to get comments added.

I do not need to know the TPM vendor.  That information would not go 
into the specification anyway.