linux-kernel - Re: [PATCH v9 7/7] arm64: dts: mediatek: mt8173-elm-hana: Mark touchscreens and trackpads as fail

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAGXv+5H8kxrr=JJsMMY5Y+HC5JqMN-bMkm7hztOzQgrbew6-rw@mail.gmail.com>
Date: Mon, 28 Oct 2024 17:13:58 +0800
From: Chen-Yu Tsai <wenst@...omium.org>
To: Doug Anderson <dianders@...omium.org>
Cc: Rob Herring <robh@...nel.org>, Saravana Kannan <saravanak@...gle.com>, 
	Matthias Brugger <matthias.bgg@...il.com>, 
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, Wolfram Sang <wsa@...nel.org>, 
	Benson Leung <bleung@...omium.org>, Tzung-Bi Shih <tzungbi@...nel.org>, 
	chrome-platform@...ts.linux.dev, devicetree@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, linux-mediatek@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, Johan Hovold <johan@...nel.org>, 
	Jiri Kosina <jikos@...nel.org>, Andy Shevchenko <andriy.shevchenko@...ux.intel.com>, 
	linux-i2c@...r.kernel.org
Subject: Re: [PATCH v9 7/7] arm64: dts: mediatek: mt8173-elm-hana: Mark
 touchscreens and trackpads as fail

On Fri, Oct 18, 2024 at 5:16 AM Doug Anderson <dianders@...omium.org> wrote:
>
> Hi,
>
> On Thu, Oct 17, 2024 at 2:42 AM Chen-Yu Tsai <wenst@...omium.org> wrote:
> >
> > Instead of having them all available, mark them all as "fail-needs-probe"
> > and have the implementation try to probe which one is present.
> >
> > Also remove the shared resource workaround by moving the pinctrl entry
> > for the trackpad interrupt line back into the individual trackpad nodes.
>
> It could be worth noting in the description that it's a really bad
> idea to pick this patch if you don't also have the patch
> ("platform/chrome: Introduce device tree hardware prober").

I found that there's a stable tag one can add to reject AUTOSEL.
Sounds like the perfect thing to add here.

> > @@ -35,6 +37,7 @@ touchscreen@40 {
> >                 hid-descr-addr = <0x0001>;
> >                 interrupt-parent = <&pio>;
> >                 interrupts = <88 IRQ_TYPE_LEVEL_LOW>;
> > +               status = "fail-needs-probe";
>
> It's a little weird that there's no pinctrl definition for the
> touchscreens but there is one for the trackpad, but that predates your
> patch and is unlikely to be a big deal.

To be honest I'm in favor of getting rid of pinctrl settings that
do nothing more than mux in a GPIO, as mentioned in my talk at ELCE.
Such settings are already implied by the interrupts or gpios properties.
The fact that the OS doesn't enforce exclusiveness between the
subsystems is not something the DT should deal with.

> >         };
> >  };
> >
> > @@ -47,6 +50,8 @@ &i2c4 {
> >         trackpad2: trackpad@2c {
> >                 compatible = "hid-over-i2c";
> >                 interrupts-extended = <&pio 117 IRQ_TYPE_LEVEL_LOW>;
> > +               pinctrl-names = "default";
> > +               pinctrl-0 = <&trackpad_irq>;
> >                 reg = <0x2c>;
>
> I should have noticed before, but officially the order above is
> slightly off. According to:
>
> https://docs.kernel.org/devicetree/bindings/dts-coding-style.html
>
> The "reg" property should be higher (right after compatible). It's not
> a new problem with your patch but since you're inserting a new
> property you might as well match the new dts style.

The entry in mt8173-elm.dtsi is also in the wrong order. I think I'll
do a patch later on to just fix it up if it's a major eyesore.

Angelo what do you think?

> In any case, nothing is a huge deal.
>
> Reviewed-by: Douglas Anderson <dianders@...omium.org>

Thanks!
ChenYu