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

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 10/26/20 5:27 PM, Kai-Heng Feng wrote:
> 
> 
>> On Oct 26, 2020, at 23:46, Hans de Goede <hdegoede@redhat.com> 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>
> 
> Acked-by: Kai-Heng Feng <kai.heng.feng@canonical.com>

Thank you. 
> And I do wonder if we should do this for all ACPI devices...

So do it with a power-domain shutdown handler in drivers/acpi/device_pm.c ?
Interesting suggestion...

Regards,

Hans



> 
> Kai-Heng
> 
>> ---
>> Changes in v2:
>> -Rebase on 5.10-rc1
>> ---
>> drivers/hid/i2c-hid/i2c-hid-core.c | 9 +++++++++
>> 1 file changed, 9 insertions(+)
>>
>> diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
>> index 786e3e9af1c9..aeff1ffb0c8b 100644
>> --- a/drivers/hid/i2c-hid/i2c-hid-core.c
>> +++ b/drivers/hid/i2c-hid/i2c-hid-core.c
>> @@ -943,6 +943,11 @@ static void i2c_hid_acpi_enable_wakeup(struct device *dev)
>> 	}
>> }
>>
>> +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 },
>> @@ -959,6 +964,8 @@ 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_enable_wakeup(struct device *dev) {}
>> +
>> +static inline void i2c_hid_acpi_shutdown(struct device *dev) {}
>> #endif
>>
>> #ifdef CONFIG_OF
>> @@ -1175,6 +1182,8 @@ 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
>>
>