linux-kernel - Re: [PATCH] TPM: Retry SaveState command in suspend path

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Date:	Tue, 16 Apr 2013 16:57:51 -0700
From:	Greg KH <gregkh@...uxfoundation.org>
To:	Kent Yoder <shpedoikal@...il.com>
Cc:	Duncan Laurie <dlaurie@...omium.org>,
	Dirk Hohndel <dirk@...ndel.org>,
	Kent Yoder <key@...ux.vnet.ibm.com>,
	Luigi Semenzato <semenzato@...omium.org>,
	tpmdd-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH] TPM: Retry SaveState command in suspend path

On Tue, Mar 19, 2013 at 10:00:02AM -0500, Kent Yoder wrote:
> Hi Duncan,
> 
> On Sun, Mar 17, 2013 at 4:56 PM, Duncan Laurie <dlaurie@...omium.org> wrote:
> > If the TPM has already been sent a SaveState command before the driver
> > is loaded it may have problems sending that same command again later.
> >
> > This issue is seen with the Chromebook Pixel due to a firmware bug in
> > the legacy mode boot path which is sending the SaveState command
> > before booting the kernel.  More information is available at
> > http://crbug.com/203524
> >
> > This change introduces a retry of the SaveState command in the suspend
> > path in order to work around this issue.  A future firmware update
> > should fix this but this is also a trivial workaround in the driver
> > that has no effect on systems that do not show this problem.
> 
>   I'm not convinced that this needs to be upstream.  The simplest
> route would seem to be to carry this out of tree until your firmware
> is fixed.

Really?  We have machines that we are using right now that need this fix
in order to work properly.

The kernel handles buggy firmware/bioses all the time, we need to work
properly on all hardware, we can't count on a firmware update ever
getting pushed out publically, and for those of us using this hardware,
we want it to work.

So, please accept this patch,

thanks,

greg l-h
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