linux-kernel - RE: [PATCH] Input: i8042 - disable KBD port on Late-2016 Razer Blade Stealth

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Message-ID: <28dc38a55c45467dad6f11e9ea459172@AcuMS.aculab.com>
Date:   Mon, 8 Apr 2019 09:55:00 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Lyude Paul' <lyude@...hat.com>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>
CC:     "stable@...r.kernel.org" <stable@...r.kernel.org>,
        Chen-Yu Tsai <wens@...e.org>,
        "linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] Input: i8042 - disable KBD port on Late-2016 Razer Blade
 Stealth

From: Lyude Paul
> Sent: 07 April 2019 23:55
> On Sun, 2019-04-07 at 15:10 -0700, Dmitry Torokhov wrote:
> > Hi Lyude,
> >
> > On Sun, Apr 07, 2019 at 05:37:34PM -0400, Lyude Paul wrote:
> > > The late 2016 model of the Razer Blade Stealth has a built-in USB
> > > keyboard, but for some reason the BIOS exposes an i8042 controller with
> > > a connected KBD port. While this fake AT Keyboard device doesn't appear
> > > to report any events, attempting to change the state of the caps lock
> > > LED on it from on to off causes the entire system to hang.
> > >
> > > So, introduce a quirk table for disabling keyboard probing by default,
> > > i8042_dmi_nokbd_table, and add this specific model of Razer laptop to
> > > that table.
> >
> > What does dmesg show about i8042 for this device? Especially line "PNP:
> > PS/2 Controller  ..."?
> >
> 
> Apr 07 18:42:46 malachite kernel: i8042: PNP: No PS/2 controller found.
> Apr 07 18:42:46 malachite kernel: i8042: Probing ports directly.
> Apr 07 18:42:46 malachite kernel: serio: i8042 KBD port at 0x60,0x64 irq 1
> Apr 07 18:42:46 malachite kernel: serio: i8042 AUX port at 0x60,0x64 irq 12
> Apr 07 18:42:46 malachite kernel: mousedev: PS/2 mouse device common for all mice

That is the 'default' probe of the ps/2 serial ports.
Looks like the BIOS is correct in not exposing the ps/2 controller.
Usually they just fail to expose the mouse when it needs a ps/2 splitter :-(

I do wonder what they've connected it to though.
It is extremely unlikely they've found an x86 chipset that doesn't
have the ps/2 serial ports at the standard io addresses.

	David

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