Before commit 67b18dfb8cfc ("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: 67b18dfb8cfc ("HID: i2c-hid: Remove runtime power management")
Cc: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
drivers/hid/i2c-hid/i2c-hid-core.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
index d9c55e30f986..04c088131e04 100644
--- a/drivers/hid/i2c-hid/i2c-hid-core.c
+++ b/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;
--
2.23.0
