Re: [PATCH v3] Add "shutdown" to "struct class".

From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
To: Josh Zimmerman <joshz@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-kernel@vger.kernel.org, "Winkler,
	Tomas" <tomas.winkler@intel.com>,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	tpmdd-devel@lists.sourceforge.net
Subject: Re: [PATCH v3] Add "shutdown" to "struct class".
Date: Mon, 15 May 2017 11:45:33 -0600	[thread overview]
Message-ID: <20170515174533.GB6229@obsidianresearch.com> (raw)
In-Reply-To: <CAHSjozBLBUpSzxrRsfnO49Thf9__MHdOmUdsX+5ST55=T2BWLA@mail.gmail.com>

On Mon, May 15, 2017 at 10:39:08AM -0700, Josh Zimmerman wrote:
> (Continuing thread from patch v1)
> > > On Sat, May 13, 2017 at 12:43:11PM +0000, Winkler, Tomas wrote:
> > > > > The TPM class has some common shutdown code that must be executed
> > > > > for all drivers. This adds some needed functionality for that
> > > >
> > > > The issue with this is, that on some platforms the only storage can be
> > > > eMMC and TPM is using it,. It has to be ensured that the storage
> > > > device won't go down before TPM2_shutdown is called.  And there is no
> > > > direct device hierarchy to ensure an orderly shutdown.
> > >
> > > Something will have to use the new device links stuff to define that
> > > dependency, but that seems unrelated to this patch?
> >
> >
> > Yep, it's not directly related to this specific patch, this is more relevant particularly to TPM2_shutdown.
> 
> Jason, do you want me to do that in my patch on the tpmdd-devel list?
> If so, mind giving me a documentation pointer or two? I'm not familiar
> with this area.

No.. Ordering power management events is something someone with
knowledge of the specific emmc platform is going to have to tackle..
It isn't really a core problem, platform specific code will have to
setup the needed device links to order power management properly..

Jason