Re: [PATCH bugfix for 5.10 2/2] iio: accel: kxcjk1013: Add support for KIOX010A ACPI DSM for setting tablet-mode

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

Hi,

On 11/14/20 5:01 PM, Jonathan Cameron wrote:
> On Tue, 10 Nov 2020 14:38:35 +0100
> Hans de Goede <hdegoede@redhat.com> wrote:
> 
>> Some 360 degree hinges (yoga) style 2-in-1 devices use 2 KXCJ91008-s
>> to allow the OS to determine the angle between the display and the base
>> of the device, so that the OS can determine if the 2-in-1 is in laptop
>> or in tablet-mode.
>>
>> On Windows both accelerometers are read by a special HingeAngleService
>> process; and this process calls a DSM (Device Specific Method) on the
>> ACPI KIOX010A device node for the sensor in the display, to let the
>> embedded-controller (EC) know about the mode so that it can disable the
>> kbd and touchpad to avoid spurious input while folded into tablet-mode.
>>
>> This notifying of the EC is problematic because sometimes the EC comes up
>> thinking that device is in tablet-mode and the kbd and touchpad do not
>> work. This happens for example on Irbis NB111 devices after a suspend /
>> resume cycle (after a complete battery drain / hard reset without having
>> booted Windows at least once). Other 2-in-1s which are likely affected
>> too are e.g. the Teclast F5 and F6 series.
>>
>> The kxcjk-1013 driver may seem like a strange place to deal with this,
>> but since it is *the* driver for the ACPI KIOX010A device, it is also
>> the driver which has access to the ACPI handle needed by the DSM.
>>
>> Add support for calling the DSM and on probe unconditionally tell the
>> EC that the device is laptop mode, fixing the kbd and touchpad sometimes
>> not working.
>>
>> Reported-and-tested-by: russianneuromancer <russianneuromancer@ya.ru>
>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> Hi Hans,
> 
> *Mutters darkly about crazy firmware hacks*
> 
> I'm fine taking this but I assume we want to backport and for that I'm
> after a fixes tag.

Good point, I guess taking the commit which originally added the
KIOX010A ACPI Hardware-ID makes the most sense:

Fixes: 7f6232e69539 ("iio: accel: kxcjk1013: Add KIOX010A ACPI Hardware-ID")

Regards,

Hans



>> ---
>>  drivers/iio/accel/kxcjk-1013.c | 36 ++++++++++++++++++++++++++++++++++
>>  1 file changed, 36 insertions(+)
>>
>> diff --git a/drivers/iio/accel/kxcjk-1013.c b/drivers/iio/accel/kxcjk-1013.c
>> index abeb0d254046..560a3373ff20 100644
>> --- a/drivers/iio/accel/kxcjk-1013.c
>> +++ b/drivers/iio/accel/kxcjk-1013.c
>> @@ -129,6 +129,7 @@ enum kx_chipset {
>>  enum kx_acpi_type {
>>  	ACPI_GENERIC,
>>  	ACPI_SMO8500,
>> +	ACPI_KIOX010A,
>>  };
>>  
>>  struct kxcjk1013_data {
>> @@ -275,6 +276,32 @@ static const struct {
>>  			      {19163, 1, 0},
>>  			      {38326, 0, 1} };
>>  
>> +#ifdef CONFIG_ACPI
>> +enum kiox010a_fn_index {
>> +	KIOX010A_SET_LAPTOP_MODE = 1,
>> +	KIOX010A_SET_TABLET_MODE = 2,
>> +};
>> +
>> +static int kiox010a_dsm(struct device *dev, int fn_index)
>> +{
>> +	acpi_handle handle = ACPI_HANDLE(dev);
>> +	guid_t kiox010a_dsm_guid;
>> +	union acpi_object *obj;
>> +
>> +	if (!handle)
>> +		return -ENODEV;
>> +
>> +	guid_parse("1f339696-d475-4e26-8cad-2e9f8e6d7a91", &kiox010a_dsm_guid);
>> +
>> +	obj = acpi_evaluate_dsm(handle, &kiox010a_dsm_guid, 1, fn_index, NULL);
>> +	if (!obj)
>> +		return -EIO;
>> +
>> +	ACPI_FREE(obj);
>> +	return 0;
>> +}
>> +#endif
>> +
>>  static int kxcjk1013_set_mode(struct kxcjk1013_data *data,
>>  			      enum kxcjk1013_mode mode)
>>  {
>> @@ -352,6 +379,13 @@ static int kxcjk1013_chip_init(struct kxcjk1013_data *data)
>>  {
>>  	int ret;
>>  
>> +#ifdef CONFIG_ACPI
>> +	if (data->acpi_type == ACPI_KIOX010A) {
>> +		/* Make sure the kbd and touchpad on 2-in-1s using 2 KXCJ91008-s work */
>> +		kiox010a_dsm(&data->client->dev, KIOX010A_SET_LAPTOP_MODE);
>> +	}
>> +#endif
>> +
>>  	ret = i2c_smbus_read_byte_data(data->client, KXCJK1013_REG_WHO_AM_I);
>>  	if (ret < 0) {
>>  		dev_err(&data->client->dev, "Error reading who_am_i\n");
>> @@ -1262,6 +1296,8 @@ static const char *kxcjk1013_match_acpi_device(struct device *dev,
>>  
>>  	if (strcmp(id->id, "SMO8500") == 0)
>>  		*acpi_type = ACPI_SMO8500;
>> +	else if (strcmp(id->id, "KIOX010A") == 0)
>> +		*acpi_type = ACPI_KIOX010A;
>>  
>>  	*chipset = (enum kx_chipset)id->driver_data;
>>  
>