linux-kernel - Re: [BISECTED] tpm CLKRUN breaks PS/2 keyboard and touchpad on Braswell system

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Message-ID: <20171219130432.tlf6tiv62nf4rreh@linux.intel.com>
Date:   Tue, 19 Dec 2017 15:04:32 +0200
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Jason Gunthorpe <jgg@...pe.ca>
Cc:     "Shaikh, Azhar" <azhar.shaikh@...el.com>,
        Javier Martinez Canillas <javierm@...hat.com>,
        James Ettle <james@...le.org.uk>,
        "linux-integrity@...r.kernel.org" <linux-integrity@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "james.l.morris@...cle.com" <james.l.morris@...cle.com>
Subject: Re: [BISECTED] tpm CLKRUN breaks PS/2 keyboard and touchpad on
 Braswell system

On Mon, Dec 18, 2017 at 01:19:02PM -0700, Jason Gunthorpe wrote:
> On Mon, Dec 18, 2017 at 07:34:29PM +0000, Shaikh, Azhar wrote:
> 
> > >IIUC, if CLKRUN_EN is enabled, then all the devices attached to the
> > >LPC bus have to support the CLKRUN protocol. My guess is that on
> > >some Braswell systems LPC power management is enabled but the TPM
> > >device doesn't have CLKRUN support.
> > 
> > I think this is what might be happening here.
> 
> That makes it a BIOS bug, not a chipset bug, and we shouldn't be
> trying to fix it like this in Linux.
> 
> Based on the original discussion I always thought this was an Intel
> chipset bug and applies to all cases.
> 
> Jason

It would not be first time when some BIOS issues are circumvented in the
kernel.

/Jarkko