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H A D | i2c-hid-core.c | diff 5c7e02a896689407555b3a10d6ed87369c70916e Mon Oct 26 16:46:06 CET 2020 Hans de Goede <hdegoede@redhat.com> HID: i2c-hid: Put ACPI enumerated devices in D3 on shutdown
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> Acked-by: Kai-Heng Feng <kai.heng.feng@canonical.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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