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Subject: Re: [PATCH v3 1/2] tpm: reduce poll sleep time in tpm_transmit()
From:   Nayna Jain <nayna@linux.vnet.ibm.com>
To:     J Freyensee <why2jjj.linux@gmail.com>,
        linux-integrity@vger.kernel.org
Cc:     zohar@linux.vnet.ibm.com, linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org, peterhuewe@gmx.de,
        jarkko.sakkinen@linux.intel.com, tpmdd@selhorst.net,
        jgunthorpe@obsidianresearch.com, patrickc@us.ibm.com
References: <20180507160733.8817-1-nayna@linux.vnet.ibm.com>
 <20180507160733.8817-2-nayna@linux.vnet.ibm.com>
 <becb898c-b778-d104-5781-899599f536d4@gmail.com>
 <107cd9f7-69a3-dbb8-1a61-541172832a0c@linux.vnet.ibm.com>
Date:   Mon, 14 May 2018 16:09:41 +0530
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On 05/10/2018 06:11 PM, Nayna Jain wrote:
>
>
> On 05/08/2018 10:04 PM, J Freyensee wrote:
>>
>>>           do {
>>> -            tpm_msleep(TPM_POLL_SLEEP);
>>> +            tpm_msleep(TPM_TIMEOUT_POLL);
>>>
>> I'm just curious why it was decided to still use tpm_msleep() here 
>> instead of usleep_range() which was used in the 2nd patch.
>
> TPM_TIMEOUT_POLL is in msec i.e. 1 msec and usleep_range() is used 
> only when timeout is needed in usecs.

Just to add bit more details:

usleep_range() is used in wait_for_tpm_stat() and get_burstcount() which 
are expected to return quickly. tpm_transmit() is a generic function 
used across all drivers and commands.
Some of the commands (eg. hash, key generation) take longer compared to 
other commands (eg. extend). The sleep time in tpm_transmit is reduced 
but kept in msecs to balance between the smaller and longer commands.

Thanks & Regards,
     - Nayna

>
>>
>> Otherwise,
>>
>> Acked-by: Jay Freyensee <why2jjj.linux@gmail.com>
>
> Thanks !!
>
> Thanks & Regards,
>     - Nayna
>
>