On Thu, 2015-09-03 at 12:56 -0300, Fernando D S Lima wrote:
> There is an error in the report descriptor of the Thinkpad Helix 2
> where
> logical minimum value (557376) is greater than logical maximum
> (491200)
> for all of the magnetic flux axis data fields. This error results in
> a
> report descriptor parsing failure that causes the sensors attached to
> the
> hub not to be detected.
>
> dmesg excerpt:
> [ 19.866905] drivers/hid/hid-core.c: logical range invalid 0x88140
> 0x77ec0
> [ 19.866914] hid-sensor-hub 0018:2047:0855.0007: item 0 1 0 8
> parsing failed
> [ 19.866926] hid-sensor-hub 0018:2047:0855.0007: parse failed
> [ 19.866933] hid-sensor-hub: probe of 0018:2047:0855.0007 failed
> with error -22
>
> Add a report fixup to change magnetic flux logical minimums to
> -557376
> for the parsing to succeed and the sensors to get detected.
> After applying the fix the sensors get detected, with corresponding
> drivers
> (hid-accel-3d,hid-gyro-3d,etc) loaded, and its possible to read their
> values.
>
> Signed-off-by: Fernando D S Lima <fernandodsl@xxxxxxxxx>
Reviewed-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
> ---
> drivers/hid/hid-sensor-hub.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/drivers/hid/hid-sensor-hub.c b/drivers/hid/hid-sensor
> -hub.c
> index 090a1ba..6c94257 100644
> --- a/drivers/hid/hid-sensor-hub.c
> +++ b/drivers/hid/hid-sensor-hub.c
> @@ -593,6 +593,20 @@ static __u8 *sensor_hub_report_fixup(struct
> hid_device *hdev, __u8 *rdesc,
> }
> }
>
> + /* Checks if the report descriptor of Thinkpad Helix 2 has a
> logical
> + * minimum for magnetic flux axis greater than the maximum
> */
> + if (hdev->product ==
> USB_DEVICE_ID_TEXAS_INSTRUMENTS_LENOVO_YOGA &&
> + *rsize == 2558 && rdesc[913] == 0x17 && rdesc[914]
> == 0x40 &&
> + rdesc[915] == 0x81 && rdesc[916] == 0x08 &&
> + rdesc[917] == 0x00 && rdesc[918] == 0x27 &&
> + rdesc[921] == 0x07 && rdesc[922] == 0x00) {
> + /* Sets negative logical minimum for mag x, y and z
> */
> + rdesc[914] = rdesc[935] = rdesc[956] = 0xc0;
> + rdesc[915] = rdesc[936] = rdesc[957] = 0x7e;
> + rdesc[916] = rdesc[937] = rdesc[958] = 0xf7;
> + rdesc[917] = rdesc[938] = rdesc[959] = 0xff;
> + }
> +
> return rdesc;
> }
>
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