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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Hans de Goede <hdegoede@redhat.com>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>
Subject: [PATCH 4.19 46/51] Input: elan_i2c - fix regulator enable count imbalance after suspend/resume
Date:   Mon,  7 Mar 2022 10:19:21 +0100
Message-Id: <20220307091638.300519420@linuxfoundation.org>
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From: Hans de Goede <hdegoede@redhat.com>

commit 04b7762e37c95d9b965d16bb0e18dbd1fa2e2861 upstream.

Before these changes elan_suspend() would only disable the regulator
when device_may_wakeup() returns false; whereas elan_resume() would
unconditionally enable it, leading to an enable count imbalance when
device_may_wakeup() returns true.

This triggers the "WARN_ON(regulator->enable_count)" in regulator_put()
when the elan_i2c driver gets unbound, this happens e.g. with the
hot-plugable dock with Elan I2C touchpad for the Asus TF103C 2-in-1.

Fix this by making the regulator_enable() call also be conditional
on device_may_wakeup() returning false.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20220131135436.29638-2-hdegoede@redhat.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/input/mouse/elan_i2c_core.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

--- a/drivers/input/mouse/elan_i2c_core.c
+++ b/drivers/input/mouse/elan_i2c_core.c
@@ -1280,17 +1280,17 @@ static int __maybe_unused elan_resume(st
 	struct elan_tp_data *data = i2c_get_clientdata(client);
 	int error;
 
-	if (device_may_wakeup(dev) && data->irq_wake) {
+	if (!device_may_wakeup(dev)) {
+		error = regulator_enable(data->vcc);
+		if (error) {
+			dev_err(dev, "error %d enabling regulator\n", error);
+			goto err;
+		}
+	} else if (data->irq_wake) {
 		disable_irq_wake(client->irq);
 		data->irq_wake = false;
 	}
 
-	error = regulator_enable(data->vcc);
-	if (error) {
-		dev_err(dev, "error %d enabling regulator\n", error);
-		goto err;
-	}
-
 	error = elan_set_power(data, true);
 	if (error) {
 		dev_err(dev, "power up when resuming failed: %d\n", error);