[PATCH AUTOSEL 5.15 01/17] Input: elantech - fix touchpad state on resume for Lenovo N24

From: Sasha Levin
Date: Tue Jul 09 2024 - 12:46:45 EST


From: Jonathan Denose <jdenose@xxxxxxxxxx>

[ Upstream commit a69ce592cbe0417664bc5a075205aa75c2ec1273 ]

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 <jdenose@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240503155020.v2.1.Ifa0e25ebf968d8f307f58d678036944141ab17e6@changeid
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/input/mouse/elantech.c | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)

diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
index 4e38229404b4b..b4723ea395eb9 100644
--- a/drivers/input/mouse/elantech.c
+++ b/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");
--
2.43.0