Input: elantech - fix touchpad state on resume for Lenovo N24

The Lenovo N24 on resume becomes stuck in a state where it
sends incorrect packets, causing elantech_packet_check_v4 to fail.
The only way for the device to resume sending the correct packets is for
it to be disabled and then re-enabled.

This change adds a dmi check to trigger this behavior on resume.

Signed-off-by: Jonathan Denose <[email protected]>
Link: https://lore.kernel.org/r/20240503155020.v2.1.Ifa0e25ebf968d8f307f58d678036944141ab17e6@changeid
Signed-off-by: Dmitry Torokhov <[email protected]>

Author: jonodeno

drivers/input/mouse/elantech.c

@@ -1476,16 +1476,47 @@ static void elantech_disconnect(struct psmouse *psmouse)
 	psmouse->private = NULL;
 }
 
+/*
+ * Some hw_version 4 models fail to properly activate absolute mode on
+ * resume without going through disable/enable cycle.
+ */
+static const struct dmi_system_id elantech_needs_reenable[] = {
+#if defined(CONFIG_DMI) && defined(CONFIG_X86)
+	{
+		/* Lenovo N24 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "81AF"),
+		},
+	},
+#endif
+	{ }
+};
+
 /*
  * Put the touchpad back into absolute mode when reconnecting
  */
 static int elantech_reconnect(struct psmouse *psmouse)
 {
+	int err;
+
 	psmouse_reset(psmouse);
 
 	if (elantech_detect(psmouse, 0))
 		return -1;
 
+	if (dmi_check_system(elantech_needs_reenable)) {
+		err = ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_DISABLE);
+		if (err)
+			psmouse_warn(psmouse, "failed to deactivate mouse on %s: %d\n",
+				     psmouse->ps2dev.serio->phys, err);
+
+		err = ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_ENABLE);
+		if (err)
+			psmouse_warn(psmouse, "failed to reactivate mouse on %s: %d\n",
+				     psmouse->ps2dev.serio->phys, err);
+	}
+
 	if (elantech_set_absolute_mode(psmouse)) {
 		psmouse_err(psmouse,
 			    "failed to put touchpad back into absolute mode.\n");