diff options
Diffstat (limited to 'drivers/hid/hid-input.c')
| -rw-r--r-- | drivers/hid/hid-input.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c index 2ba6bf69b7d0..53e54855c366 100644 --- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -1128,18 +1128,26 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct /* * Ignore out-of-range values as per HID specification, - * section 5.10 and 6.2.25. + * section 5.10 and 6.2.25, when NULL state bit is present. + * When it's not, clamp the value to match Microsoft's input + * driver as mentioned in "Required HID usages for digitizers": + * https://msdn.microsoft.com/en-us/library/windows/hardware/dn672278(v=vs.85).asp * * The logical_minimum < logical_maximum check is done so that we * don't unintentionally discard values sent by devices which * don't specify logical min and max. */ if ((field->flags & HID_MAIN_ITEM_VARIABLE) && - (field->logical_minimum < field->logical_maximum) && - (value < field->logical_minimum || - value > field->logical_maximum)) { - dbg_hid("Ignoring out-of-range value %x\n", value); - return; + (field->logical_minimum < field->logical_maximum)) { + if (field->flags & HID_MAIN_ITEM_NULL_STATE && + (value < field->logical_minimum || + value > field->logical_maximum)) { + dbg_hid("Ignoring out-of-range value %x\n", value); + return; + } + value = clamp(value, + field->logical_minimum, + field->logical_maximum); } /* |