Re: [PATCH V2 RESEND] Input: synaptics - disable InterTouch on ThinkPad T440p (board id 2722)

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

On Thu, Sep 10, 2026 at 12:44:25PM -0400, Raphaël Larocque wrote:
> The Lenovo ThinkPad T440p (PNP ID LEN0036, board id 2722) has a
> Synaptics touchpad whose SMBus companion is not ready at boot and
> takes roughly 200 seconds to appear. During this window the touchpad
> and TrackPoint are completely unresponsive on approximately 50% of
> boots, making the machine unusable until the companion finally
> registers.
> 
> The device is in the topbuttonpad_pnp_ids[] SMBus allowlist, so the
> kernel attempts to use SMBus/RMI4 mode by default. When the companion
> is not ready, psmouse_smbus_init() leaves breadcrumbs and returns
> -EAGAIN, the PS/2 fallback path is taken, but the device does not
> function properly until the companion appears and RMI4 takes over.
> 
> Disable SMBus InterTouch for board id 2722 so the touchpad and
> TrackPoint work immediately via PS/2 from boot. Users can still force
> SMBus with psmouse.synaptics_intertouch=1 if needed.
> 
> Tested-by: Raphaël Larocque <rlarocque@disroot.org>
> Signed-off-by: Raphaël Larocque <rlarocque@disroot.org>

Applied, thank you.

-- 
Dmitry