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

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Date:	Wed, 17 Apr 2013 09:18:48 -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>,
	TPM Device Driver List <tpmdd-devel@...ts.sourceforge.net>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH] TPM: Retry SaveState command in suspend path

On Wed, Apr 17, 2013 at 09:54:24AM -0500, Kent Yoder wrote:
> On Tue, Apr 16, 2013 at 6:57 PM, Greg KH <gregkh@...uxfoundation.org> wrote:
> > 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.
> 
>   That makes sense -- on first read I thought this was an issue with
> Chrome OS only.  I see now this is an issue with reinstalling other
> OS's over Chrome.  I've staged this over here:
> 
> git://github.com/shpedoikal/linux.git tpmdd-04-17-13
> 
> and I'll push this to James later today.

Thank you very much, it's appreciated.  I'll watch out for it to hit
Linus's tree and add it to the -stable releases as well.

greg k-h
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