[PATCH] Input: synaptics - limit T440p InterTouch quirk to LEN0036

[PATCH] Input: synaptics - limit T440p InterTouch quirk to LEN0036

[R. Larocque]

From: "Raphaël Larocque" <rlarocque@disroot.org>

The ThinkPad L440 also uses board id 2722, but does not have the SMBus
initialization problem seen on the T440p. On the L440, the SMBus
companion becomes available shortly after psmouse probes, allowing the
touchpad to use SMBus/RMI4 normally.

The T440p's quirk is currently applied to all Synaptics touchpads with
board id 2722, unnecessarily disabling SMBus InterTouch on the L440,
as reported by Daniel Salmun.

Restrict the quirk to PNP ID LEN0036, which identifies the T440p, so
that other devices sharing board id 2722 retain their normal
SMBus/RMI4 operation.

Reported-by: Daniel Salmun <salmundani@gmail.com>
Link: https://lore.kernel.org/all/20260925230039.236786-1-salmundani@gmail.com/
Fixes: 26eb3d92c7a4 ("Input: synaptics - disable InterTouch on ThinkPad T440p (board id 2722)")
Cc: stable@vger.kernel.org
Signed-off-by: Raphaël Larocque <rlarocque@disroot.org>
---
 drivers/input/mouse/synaptics.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index a8ce89d41faa..cc1e0bb4325b 100644
--- a/drivers/input/mouse/synaptics.c
+++ b/drivers/input/mouse/synaptics.c
@@ -1839,8 +1839,10 @@ static int synaptics_setup_intertouch(struct psmouse *psmouse,
 			return -ENXIO;
 		}
 
-		/* Disable intertouch on known-broken board revisions */
-		if (info->board_id == 2722) {
+		/* Disable intertouch on known-broken T440p board revisions */
+		if (psmouse_matches_pnp_id(psmouse,
+			(const char * const []){"LEN0036", NULL}) &&
+		    info->board_id == 2722) {
 			psmouse_info(psmouse,
 				     "Disabling intertouch for board id %u\n",
 				     info->board_id);
-- 
2.55.0

Re: [PATCH] Input: synaptics - limit T440p InterTouch quirk to LEN0036

[Dmitry Torokhov]

On Sat, Sep 26, 2026 at 08:58:10PM -0400, R. Larocque wrote:
> From: "Raphaël Larocque" <rlarocque@disroot.org>
> 
> The ThinkPad L440 also uses board id 2722, but does not have the SMBus
> initialization problem seen on the T440p. On the L440, the SMBus
> companion becomes available shortly after psmouse probes, allowing the
> touchpad to use SMBus/RMI4 normally.
> 
> The T440p's quirk is currently applied to all Synaptics touchpads with
> board id 2722, unnecessarily disabling SMBus InterTouch on the L440,
> as reported by Daniel Salmun.
> 
> Restrict the quirk to PNP ID LEN0036, which identifies the T440p, so
> that other devices sharing board id 2722 retain their normal
> SMBus/RMI4 operation.
> 
> Reported-by: Daniel Salmun <salmundani@gmail.com>
> Link: https://lore.kernel.org/all/20260925230039.236786-1-salmundani@gmail.com/
> Fixes: 26eb3d92c7a4 ("Input: synaptics - disable InterTouch on ThinkPad T440p (board id 2722)")
> Cc: stable@vger.kernel.org
> Signed-off-by: Raphaël Larocque <rlarocque@disroot.org>

Swapped the condition (since integer check is cheaper) and applied,
thank you.

-- 
Dmitry