platform/x86: ideapad-laptop: Only toggle ps2 aux port on/off on select models

Recently there have been multiple patches to disable the ideapad-laptop's
touchpad control code, because it is causing issues on various laptops:

Commit d69cd7eea93e ("platform/x86: ideapad-laptop: Disable touchpad_switch for ELAN0634")
Commit a231224a601c ("platform/x86: ideapad-laptop: Disable touchpad_switch")

The turning on/off of the ps2 aux port was added specifically for
the IdeaPad Z570, where the EC does toggle the touchpad on/off LED and
toggles the value returned by reading VPCCMD_R_TOUCHPAD, but it does not
actually turn on/off the touchpad.

The ideapad-laptop code really should not be messing with the i8042
controller on all devices just for this special case.

Add a new ctrl_ps2_aux_port flag set based on a DMI based allow-list
for devices which need this workaround, populating it with just
the Ideapad Z570 for now.

This also adds a module parameter so that this behavior can easily
be enabled on other models which may need it.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Tested-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Tested-by: Maxim Mikityanskiy <maxtram95@gmail.com>
Link: https://lore.kernel.org/r/20221117110244.67811-4-hdegoede@redhat.com

diff --git a/drivers/platform/x86/ideapad-laptop.c b/drivers/platform/x86/ideapad-laptop.c
index eb0b1ec..1d86fb9 100644 (file)
--- a/drivers/platform/x86/ideapad-laptop.c
+++ b/drivers/platform/x86/ideapad-laptop.c
@@ -143,6 +143,7 @@ struct ideapad_private {
                bool hw_rfkill_switch     : 1;
                bool kbd_bl               : 1;
                bool touchpad_ctrl_via_ec : 1;
+               bool ctrl_ps2_aux_port    : 1;
                bool usb_charging         : 1;
        } features;
        struct {
@@ -174,6 +175,12 @@ MODULE_PARM_DESC(set_fn_lock_led,
        "Enable driver based updates of the fn-lock LED on fn-lock changes. "
        "If you need this please report this to: platform-driver-x86@vger.kernel.org");
 
+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");
+
 /*
  * shared data
  */
@@ -1507,7 +1514,8 @@ static void ideapad_sync_touchpad_state(struct ideapad_private *priv, bool send_
         * touchpad off and on. We send KEY_TOUCHPAD_OFF and
         * KEY_TOUCHPAD_ON to not to get out of sync with LED
         */
-       i8042_command(&param, value ? I8042_CMD_AUX_ENABLE : I8042_CMD_AUX_DISABLE);
+       if (priv->features.ctrl_ps2_aux_port)
+               i8042_command(&param, value ? I8042_CMD_AUX_ENABLE : I8042_CMD_AUX_DISABLE);
 
        if (send_events) {
                ideapad_input_report(priv, value ? 67 : 66);
@@ -1615,6 +1623,23 @@ static const struct dmi_system_id hw_rfkill_list[] = {
        {}
 };
 
+/*
+ * On some models the EC toggles the touchpad muted LED on touchpad toggle
+ * hotkey presses, but the EC does not actually disable the touchpad itself.
+ * On these models the driver needs to explicitly enable/disable the i8042
+ * (PS/2) aux port.
+ */
+static const struct dmi_system_id ctrl_ps2_aux_port_list[] = {
+       {
+       /* Lenovo Ideapad Z570 */
+       .matches = {
+               DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+               DMI_MATCH(DMI_PRODUCT_VERSION, "Ideapad Z570"),
+               },
+       },
+       {}
+};
+
 static const struct dmi_system_id no_touchpad_switch_list[] = {
        {
        .ident = "Lenovo Yoga 3 Pro 1370",
@@ -1642,6 +1667,8 @@ static void ideapad_check_features(struct ideapad_private *priv)
                set_fn_lock_led || dmi_check_system(set_fn_lock_led_list);
        priv->features.hw_rfkill_switch =
                hw_rfkill_switch || dmi_check_system(hw_rfkill_list);
+       priv->features.ctrl_ps2_aux_port =
+               ctrl_ps2_aux_port || dmi_check_system(ctrl_ps2_aux_port_list);
 
        /* Most ideapads with ELAN0634 touchpad don't use EC touchpad switch */
        if (acpi_dev_present("ELAN0634", NULL, -1))