Re: [PATCH v3] platform/x86: ideapad-laptop: do not poke keyboard controller

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

Hi Rong,

On Sat, Oct 24, 2026 at 10:15:56AM +0800, Rong Zhang wrote:
> >  static bool ctrl_ps2_aux_port;
> >  module_param(ctrl_ps2_aux_port, bool, 0444);
> >  MODULE_PARM_DESC(ctrl_ps2_aux_port,
> > -		 "Enable driver based PS/2 aux port en-/dis-abling on touchpad on/off toggle. If you need this please report this to: platform-driver-x86@vger.kernel.org");
> > +		 "Enable driver based suppression of touchpad events on touchpad on/off toggle. If you need this please report this to: platform-driver-x86@vger.kernel.org");
>
> By re-purposing ctrl_ps2_aux_port, you are breaking its existing users
> *silently*.

I'm not?

>
> Please don't do so, but rename module parameter to reflect the new
> behavior. In this manner, the existing users should at least see some
> clues in kmsg.

The purpose of ctrl_ps2_aux_port (introduced in commit c69e7d843d2c
("platform/x86: ideapad-laptop: Only toggle ps2 aux port on/off on
select models")) is to let the driver disable and re-enable the PS/2
touchpad on models where pressing the touchpad toggle hotkey only
toggles the LED in the EC without muting the touchpad itself.

This patch still targets the exact same i8042 PS/2 touchpad devices and
achieves the exact same user-visible behavior (muting and unmuting the
touchpad when the hotkey is pressed), just by filtering events in the
input layer instead of poking the 8042 controller behind the i8042 and
psmouse drivers' backs.

Anyone currently passing ideapad_laptop.ctrl_ps2_aux_port=1 on their
kernel command line or in modprobe configuration will continue to have a
working touchpad toggle. Renaming the module parameter, on the other
hand, is what would actually break those existing users by causing the
module to reject the parameter and stop muting their touchpad.

Thanks.

-- 
Dmitry