HID: i2c-hid: Send power-on command after reset

Before commit 67b18df ("HID: i2c-hid: Remove runtime power
management"), any i2c-hid touchscreens would typically be runtime-suspended
between the driver loading and Xorg or a Wayland compositor opening it,
causing it to be resumed again. This means that before this change,
we would call i2c_hid_set_power(OFF), i2c_hid_set_power(ON) before the
graphical session would start listening to the touchscreen.

It turns out that at least some SIS touchscreens, such as the one found
on the Asus T100HA, need a power-on command after reset, otherwise they
will not send any events.

Fixes: 67b18df ("HID: i2c-hid: Remove runtime power management")
Cc: Kai-Heng Feng <[email protected]>
Signed-off-by: Hans de Goede <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>

Author: jwrdegoede

drivers/hid/i2c-hid/i2c-hid-core.c

@@ -447,8 +447,12 @@ static int i2c_hid_hwreset(struct i2c_client *client)
 	if (ret) {
 		dev_err(&client->dev, "failed to reset device.\n");
 		i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
+		goto out_unlock;
 	}
 
+	/* At least some SIS devices need this after reset */
+	ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
+
 out_unlock:
 	mutex_unlock(&ihid->reset_lock);
 	return ret;