linux-kernel - Re: [PATCH 0/4] tpm: fix PS/2 devices not working on Braswell systems due CLKRUN enabled

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Date:   Fri, 22 Dec 2017 20:39:30 +0200
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Hans de Goede <hdegoede@...hat.com>
Cc:     Javier Martinez Canillas <javierm@...hat.com>,
        linux-kernel@...r.kernel.org, James Ettle <james@...le.org.uk>,
        Azhar Shaikh <azhar.shaikh@...el.com>,
        Arnd Bergmann <arnd@...db.de>, Peter Huewe <peterhuewe@....de>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-integrity@...r.kernel.org
Subject: Re: [PATCH 0/4] tpm: fix PS/2 devices not working on Braswell
 systems due CLKRUN enabled

On Wed, Dec 20, 2017 at 12:43:39PM +0100, Hans de Goede wrote:
> Note I'm just reading along here, but I'm wondering if both the TPM
> and now also some PS/2 controllers need CLK_RUN to be disabled,
> why don't we just disable it once permanently and be done with it?
> 
> It seems that on machines with a PS/2 controller connected to
> the LPC bus the BIOS is already doing this, so I've a feeling that
> it not being done on devices with a TPM is a bug in the firmware
> there and we should just disable it everywhere (and probably
> find a better place then the TPM driver to do the disabling).
> 
> Note this is just an observation, I could be completely wrong here,
> but I've a feeling that just disabling CLKRUN all together is the
> right thing to do and that seems like an easier fix to me.

Agreed. Thanks for noting this. Right now, I would just apply TPM
driver specific fixes.

/Jarkko