Received-SPF: pass (google.com: domain of linux-kernel+bounces-66179-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
Precedence: bulk
MIME-Version: 1.0
In-Reply-To: <CAD=FV=WE4bgwTWTKjPbQR9RCt-SEVZXfQtXoaXAjvTiZiMr=wA@mail.gmail.com>
References: <20240210070934.2549994-1-swboyd@chromium.org> <20240210070934.2549994-19-swboyd@chromium.org>
 <CAD=FV=WE4bgwTWTKjPbQR9RCt-SEVZXfQtXoaXAjvTiZiMr=wA@mail.gmail.com>
From: Stephen Boyd <swboyd@chromium.org>
User-Agent: alot/0.10
Date: Wed, 14 Feb 2024 16:10:36 -0800
Message-ID: <CAE-0n53H-WPSr4tnmjq2Z54daKYD3PPzmxy28GsYAd29MTXiWA@mail.gmail.com>
Subject: Re: [PATCH 18/22] dt-bindings: chrome: Add binding for ChromeOS Pogo
 pin connector
To: Doug Anderson <dianders@chromium.org>
Cc: chrome-platform@lists.linux.dev, linux-kernel@vger.kernel.org, 
	patches@lists.linux.dev, linux-arm-kernel@lists.infradead.org, 
	devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org, 
	Pin-yen Lin <treapking@chromium.org>, Rob Herring <robh+dt@kernel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, Conor Dooley <conor+dt@kernel.org>, 
	Benson Leung <bleung@chromium.org>, Guenter Roeck <groeck@chromium.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

Quoting Doug Anderson (2024-02-13 17:17:34)
> Hi,
>
> On Fri, Feb 9, 2024 at 11:10=E2=80=AFPM Stephen Boyd <swboyd@chromium.org=
> wrote:
> >
> > Describe the set of pins used to connect the detachable keyboard on
> > detachable ChromeOS devices. The set of pins is called the "pogo pins".
> > It's basically USB 2.0 with an extra pin for base detection. We expect
> > to find a keyboard on the other side of this connector with a specific
> > vid/pid, so describe that as a child device at the port of the usb
> > device connected upstream.
>
> Can you remind me what the side effects would be if a different
> VID/PID shows up there? I know it's not an end-user scenario, but I
> have a pre-production "coachz" keyboard that's actually programmed
> incorrectly and shows up as the wrong PID. Presumably I could either
> throw the old hardware away or figure out a way to re-program it and
> it's really not a big deal, but just curious what happens...

As far as I know nothing happens besides ChromeOS userspace treats the
keyboard as "external" so things like smarter base detection, e.g.
wraparound keyboard detection or kickstand mode, may not work. I think
you get a popup box telling you the keyboard isn't the trusted one.