From: Stefan Berger <stefanb@linux.vnet.ibm.com>
To: Jeff Layton <jlayton@poochiereds.net>
Cc: linux-kernel@vger.kernel.org, tpmdd-devel@lists.sourceforge.net,
"debora@linux.vnet.ibm.com" <debora@linux.vnet.ibm.com>,
Rajiv Andrade <srajiv@linux.vnet.ibm.com>
Subject: Re: TPM chip prevents machine from suspending
Date: Tue, 29 Mar 2011 08:25:01 -0400 [thread overview]
Message-ID: <4D91CF9D.3050500@linux.vnet.ibm.com> (raw)
In-Reply-To: <20110329080856.1726dfaa@tlielax.poochiereds.net>
On 03/29/2011 08:08 AM, Jeff Layton wrote:
> On Mon, 28 Mar 2011 19:10:55 -0400
> Stefan Berger<stefanb@linux.vnet.ibm.com> wrote:
>
>> Ok, so this error code means TPM_INVALID_POSTINIT (not a posix code)
>> and means that this command was received in the wrong sequence relative
>> to a TPM_Startup command. Well, what's supposed to be happening is this:
>>
>> When the machines (S3) suspends then the OS needs to send a
>> TPM_SaveState() to the TPM. This is done by the Linux driver. Once the
>> VM resumes, the BIOS is supposed to send a TPM_Startup(ST_STATE) to the TPM.
>>
>> Now the fun starts when a BIOS isn't doing that (even though the spec
>> says it's supposed to), which could very well be the case in your case
>> (don't know what broken BIOSes are out there... Did it ever work before
>> with the TPM driver in the kernel ?). I could try to send you a small
>> tool that you would have to run from user space upon resume so that we
>> can see that this error goes away. If that's verified we could
>> subsequently write a patch for the TPM driver to also send the
>> TPM_Startup(ST_STATE) to the TPM, which then in the case of most BIOSes
>> would be the 2nd time that the TPM receives such a command. I think TPMs
>> should be able to digest this 2nd TPM_Startup() well, but I'd have to
>> check -- but really we would ill-fix it just because of one (possibly)
>> buggy BIOS.
>>
>> The failure of the 2nd suspend then likely stems from the TPM not
>> accepting the TPM_SaveState() anymore since it hasn't seen the
>> TPM_Startup(ST_STATE) that we expected the BIOS to send.
>>
> Yep. That program fixed the problem. When I run it after a resume, I
> can then cat the caps file and get output from it, and the machine will
> successfully suspend again.
Well, we now could (once) probe the TPM after the resume and send a test
command to it and see whether it returns error code 38 and if so send
the TPM_Startup() from the driver -- as a work-around for your broken BIOS.
>> Another possibility would be for you to check for BIOS updates from the
>> laptop manufacturer...
>>
> This is actually a desktop machine and the BIOS for the motherboard is
> at the latest version, though it is quite old -- 2007/09/01. For the
> record this is a:
>
> Foxconn 6150BK8MC
>
> I'm actually not using the TPM in this thing at all. I'd be just as
> happy if there were some way to disable it. Unfortunately, the option
> in the BIOS to do this doesn't seem to actually work. When I set "TPM
> Control" in the BIOS to "Disable" it always ends up reset back to "No
> Change". I'd report both problems to the mfr, but this thing is long
> out of warranty and I'm pretty sure they won't care.
>
> Is there some way short of recompiling with CONFIG_TCG_* turned off
> to disable the TPM driver at boot time?
>
As far as I know, 'no'. I'd defer it to the maintainers as to how they
would want to solve your particular problem... either by using above
work-around, which would be more transparent, or actively having to turn
the driver off with a command line parameter.
Stefan
next prev parent reply other threads:[~2011-03-29 12:25 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-28 14:08 TPM chip prevents machine from suspending Jeff Layton
2011-03-28 17:25 ` Stefan Berger
2011-03-28 18:12 ` Jeff Layton
2011-03-28 19:45 ` Jeff Layton
2011-03-28 19:57 ` Sisir Koppaka
2011-03-28 20:16 ` Jeff Layton
2011-03-28 20:32 ` Sisir Koppaka
2011-03-28 23:10 ` Stefan Berger
2011-03-29 0:19 ` Stefan Berger
2011-03-29 12:08 ` Jeff Layton
2011-03-29 12:25 ` Stefan Berger [this message]
2011-03-29 12:30 ` Jeff Layton
2011-03-29 14:30 ` Rajiv Andrade
2011-03-29 15:03 ` Stefan Berger
2011-03-30 19:43 ` [tpmdd-devel] " Eric Paris
2012-01-21 17:01 ` [Sony Vaio TX3] TPM chip prevents machine from suspending a second time Jonathan Nieder
2012-01-23 20:52 ` Stefan Berger
2012-01-29 10:49 ` John Hughes
2012-01-29 18:22 ` Stefan Berger
2012-01-30 9:10 ` John Hughes
2012-02-26 15:44 ` Jonathan Nieder
2012-05-03 15:34 ` John Hughes
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