media: atomisp: Put sensor ACPI devices in D3 before disable ACPI power-resources

The device core will call ACPI to turn the device (i2c_client) for a sensor
on / put it in D0 before calling its probe() method.

This takes a reference on all of the ACPI power-resources belonging to
the device. Since the atomisp_gmin_platform code disables ACPI
power-resource management and does its own pm, this reference never gets
released.

This is a problem for ACPI power-resources which are shared with other
devices since those now never get turned off again (nor back on again).

Explicitly put the device in D3 before disabling the ACPI power-resource
management.

Note that atomisp_register_i2c_module() runs near the end of the sensor
driver's probe() function, after the driver is done with probing the hw.
So the power-resouces (the same resources as directly controlled by
the atomisp platform code) getting turned off (a second time, as they are
already off) is not a problem.
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c

@@ -161,6 +161,14 @@ int atomisp_register_i2c_module(struct v4l2_subdev *subdev,
 	 * tickled during suspend/resume.  This has caused power and
 	 * performance issues on multiple devices.
 	 */
+
+	/*
+	 * Turn off the device before disabling ACPI power resources
+	 * (the sensor driver has already probed it at this point).
+	 * This avoids leaking the reference count of the (possibly shared)
+	 * ACPI power resources which were enabled/referenced before probe().
+	 */
+	acpi_device_set_power(adev, ACPI_STATE_D3_COLD);
 	adev->power.flags.power_resources = 0;
 
 	for (i = 0; i < MAX_SUBDEVS; i++)