From: "Michal Suchánek" <msuchanek@suse.de>
To: Ken Goldman <kgold@linux.vnet.ibm.com>
Cc: linux-ima-devel@lists.sourceforge.net,
linux-security-module@vger.kernel.org,
tpmdd-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org
Subject: Re: [tpmdd-devel] [PATCH] tpm: improve tpm_tis send() performance by ignoring burstcount
Date: Wed, 16 Aug 2017 12:24:23 +0200 [thread overview]
Message-ID: <20170816122423.315817c7@kitsune.suse.cz> (raw)
In-Reply-To: <869cc1b1-0836-a53b-31d7-9fec50d8cc52@linux.vnet.ibm.com>
On Tue, 15 Aug 2017 18:02:57 -0400
Ken Goldman <kgold@linux.vnet.ibm.com> wrote:
> On 8/13/2017 7:53 PM, msuchanek wrote:
> > About 500 out of 700 mainboards sold today has a PS/2 port which is
> > probably due to prevalence of legacy devices and usbhid limitations.
> >
> > Similarily many boards have serial and parallel hardware ports.
> >
> > In all diagrams detailed enough to show these ports I have seen them
> > attached to the LPC bus.
>
> Do these boards have a TPM? Remember that the TPM requires special
> LPC bus cycles.
Out of nearly 700 boards over 500 have PS/2 connector and over 400
have TPM slot (which is subset of the PS/2 enabled boards). Some more
possibly have on-board TPM chip.
>
> Even if so, the TPM LPC bus wait states are less than a usec. My
> thought is that it's unlikely that any device (serial port, mouse,
> keyboard, printer) will be adversely affected.
Yes, in theory this is negligible. So unless there is a possibility
these wait states chain or the device otherwise takes over the bus for
extended period of time this should be fine.
Thanks
Michal
next prev parent reply other threads:[~2017-08-16 10:24 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-07 11:46 [PATCH] tpm: improve tpm_tis send() performance by ignoring burstcount Nayna Jain
2017-08-07 11:52 ` Peter Huewe
2017-08-07 14:25 ` Nayna
2017-08-08 21:50 ` Jarkko Sakkinen
2017-08-08 19:11 ` Jarkko Sakkinen
2017-08-09 20:23 ` [tpmdd-devel] " Ken Goldman
2017-08-09 20:43 ` Aw: " Peter Huewe
2017-08-11 21:54 ` Ken Goldman
[not found] ` <20170814101046.5hqrkaqmfvl7ugwj@linux.intel.com>
2017-08-16 19:51 ` Ken Goldman
2017-08-09 20:25 ` Ken Goldman
2017-08-09 21:00 ` Aw: " Peter Huewe
2017-08-11 11:14 ` Jarkko Sakkinen
2017-08-11 15:30 ` Mimi Zohar
2017-08-14 10:51 ` Jarkko Sakkinen
2017-08-14 10:56 ` Jarkko Sakkinen
2017-08-14 12:03 ` Mimi Zohar
2017-08-15 6:08 ` Jarkko Sakkinen
2017-08-14 12:12 ` Mimi Zohar
2017-08-15 6:09 ` Jarkko Sakkinen
2017-08-11 21:32 ` Aw: " Ken Goldman
2017-08-13 23:53 ` msuchanek
2017-08-15 22:02 ` Ken Goldman
2017-08-16 10:24 ` Michal Suchánek [this message]
2017-08-11 21:42 ` [Linux-ima-devel] " Ken Goldman
2017-08-08 19:07 ` Jarkko Sakkinen
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