[PATCH 26/57] media: atomisp: Put sensor ACPI devices in D3 before disable ACPI power-resources

Hans de Goede
2023-01-23T12:54:28Z

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.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c b/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c
index 1e943c423893..2b9d68141520 100644
--- a/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c
+++ b/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c
@@ -159,6 +159,14 @@ 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++)
--
2.39.0