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[D/E/OEM-OSP1-B,2/2] HID: i2c-hid: Send power-on command after reset

Message ID 20191125143334.31405-3-kai.heng.feng@canonical.com
State New
Headers show
Series None | expand

Commit Message

Kai-Heng Feng Nov. 25, 2019, 2:33 p.m. UTC 
From: Hans de Goede <hdegoede@redhat.com>

BugLink: https://bugs.launchpad.net/bugs/1853842

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@canonical.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
(cherry picked from commit 43b7029f475e7497da1de1f4a1742241812bf266)
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/hid/i2c-hid/i2c-hid-core.c | 4 ++++
 1 file changed, 4 insertions(+)
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Patch

diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
index d75b8a803b5a..4009f665a230 100644
--- a/drivers/hid/i2c-hid/i2c-hid-core.c
+++ b/drivers/hid/i2c-hid/i2c-hid-core.c
@@ -449,8 +449,12 @@  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;