[PATCH] HID: i2c-hid: Put ACPI enumerated devices in D3 on shutdown

[PATCH] HID: i2c-hid: Put ACPI enumerated devices in D3 on shutdown

[Hans de Goede]

The i2c-hid driver would quietly fail to probe the i2c-hid sensor-hub
with an ACPI device-id of SMO91D0 every other boot.

Specifically, the i2c_smbus_read_byte() "Make sure there is something at
this address" check would fail every other boot.

It seems that the BIOS does not properly reset/power-cycle the device
leaving it in a confused state where it refuses to respond to i2c-xfers.
On boots where probing the device failed, the driver-core puts the device
in D3 after the probe-failure, which causes the probe to succeed the next
boot.

Putting the device in D3 from the shutdown-handler fixes the sensors not
working every other boot.

This has been tested on both a Lenovo Miix 2-10 and a Dell Venue 8 Pro 5830
both of which use an i2c-hid sensor-hub with an ACPI id of SMO91D0.

Note that it is safe to call acpi_device_set_power() with a NULL pointer
as first argument, so on none ACPI enumerated devices this change is a
no-op.

Cc: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/hid/i2c-hid/i2c-hid-core.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
index dbd04492825d..b303a1dd0e3f 100644
--- a/drivers/hid/i2c-hid/i2c-hid-core.c
+++ b/drivers/hid/i2c-hid/i2c-hid-core.c
@@ -935,6 +935,11 @@ static void i2c_hid_acpi_fix_up_power(struct device *dev)
 		acpi_device_fix_up_power(adev);
 }
 
+static void i2c_hid_acpi_shutdown(struct device *dev)
+{
+	acpi_device_set_power(ACPI_COMPANION(dev), ACPI_STATE_D3_COLD);
+}
+
 static const struct acpi_device_id i2c_hid_acpi_match[] = {
 	{"ACPI0C50", 0 },
 	{"PNP0C50", 0 },
@@ -949,6 +954,7 @@ static inline int i2c_hid_acpi_pdata(struct i2c_client *client,
 }
 
 static inline void i2c_hid_acpi_fix_up_power(struct device *dev) {}
+static inline void i2c_hid_acpi_shutdown(struct device *dev) {}
 #endif
 
 #ifdef CONFIG_OF
@@ -1163,6 +1169,8 @@ static void i2c_hid_shutdown(struct i2c_client *client)
 
 	i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
 	free_irq(client->irq, ihid);
+
+	i2c_hid_acpi_shutdown(&client->dev);
 }
 
 #ifdef CONFIG_PM_SLEEP
-- 
2.28.0