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From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
To: Kent Yoder <shpedoikal@gmail.com>
Cc: linux-kernel@vger.kernel.org, tpmdd-devel@lists.sourceforge.net
Subject: Re: [tpmdd-devel] [PATCH] TPM: Work around buggy TPMs that block during continue self test
Date: Fri, 25 Jan 2013 13:25:38 -0700	[thread overview]
Message-ID: <20130125202538.GA16038@obsidianresearch.com> (raw)
In-Reply-To: <CAM0nabE9qORsD1bMDm6EUZogPqb2m-X8rZ-xVqJecM7oJyaciw@mail.gmail.com>

On Tue, Jan 22, 2013 at 05:29:23PM -0600, Kent Yoder wrote:
> Hi Jason,
> 
> On Wed, Nov 21, 2012 at 3:15 PM, Jason Gunthorpe
> <jgunthorpe@obsidianresearch.com> wrote:
> > We've been testing an alternative TPM for our embedded products and
> > found random kernel boot failures due to time outs after the continue
> > self test command.
> >
> > This was happening randomly, and has been *very* hard to track down, but it
> > looks like with this chip there is some kind of race with the tpm_tis_status()
> > check of TPM_STS_COMMAND_READY. If things get there 'too fast' then
> > it sees the chip is ready, or tpm_tis_ready() works. Otherwise it takes
> > somewhere over 400ms before the chip will return TPM_STS_COMMAND_READY.
> >
> > Adding some delay after tpm_continue_selftest() makes things reliably
> > hit the failure path, otherwise it is a crapshot.
> 
>   I've staged this patch here, please test:
> 
> https://github.com/shpedoikal/linux.git tpmdd-01-22-13

Thanks Kent, I will try to test your branch next week, if I am able.

Can you also grab

https://github.com/jgunthorpe/linux/commit/98b2a198b43b41b0535200bf475160786398f114

And did you have any comments on:

https://github.com/jgunthorpe/linux/commit/9981e3e622bf702394982117134bed731ffd6f7e

Both were posted to the list a bit ago.

Regards,
-- 
Jason Gunthorpe <jgunthorpe@obsidianresearch.com>        (780)4406067x832
Chief Technology Officer, Obsidian Research Corp         Edmonton, Canada

  reply	other threads:[~2013-01-25 20:25 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-21 21:15 [PATCH] TPM: Work around buggy TPMs that block during continue self test Jason Gunthorpe
2013-01-22 23:29 ` [tpmdd-devel] " Kent Yoder
2013-01-25 20:25   ` Jason Gunthorpe [this message]
     [not found]     ` <20130128141153.GA3060@ennui.austin.ibm.com>
2013-02-01 22:38       ` Kent Yoder
2013-02-01 23:03         ` Jason Gunthorpe
2013-02-03 23:02     ` Peter Hüwe

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