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

Before commit 67b18dfb8c ("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: 67b18dfb8c ("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>
This commit is contained in:
Hans de Goede 2019-10-20 23:47:18 +02:00 committed by Jiri Kosina
parent 09f3dbe474
commit 43b7029f47
1 changed files with 4 additions and 0 deletions
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4
drivers/hid/i2c-hid/i2c-hid-core.c
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@ -447,8 +447,12 @@ static int i2c_hid_hwreset(struct i2c_client *client)
if (ret) { if (ret) {
dev_err(&client->dev, "failed to reset device.\n"); dev_err(&client->dev, "failed to reset device.\n");
i2c_hid_set_power(client, I2C_HID_PWR_SLEEP); 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: out_unlock:
mutex_unlock(&ihid->reset_lock); mutex_unlock(&ihid->reset_lock);
return ret; return ret;