Re: [PATCH v2] HID: i2c-hid: Put ACPI enumerated devices in D3 on shutdown

[Jiri Kosina <jikos@kernel.org>]

On Mon, 26 Oct 2020, Hans de Goede wrote:

> 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>

Applied, thanks.

-- 
Jiri Kosina
SUSE Labs