On 03/19/2013 10:25 PM, Henrik Rydberg wrote:
> Hi Benjamin,
>
>> There is no need to register an input device containing no events.
>> This allows drivers using the quirk MULTI_INPUT to register one input
>> per report effectively used.
>>
>> For backward compatibility, we need to add a quirk to request
>> this behavior.
>>
>> Signed-off-by: Benjamin Tissoires <benjamin.tissoi...@redhat.com>
>> ---
>> drivers/hid/hid-input.c | 77
>> +++++++++++++++++++++++++++++++++++++++++++++++++
>> include/linux/hid.h | 1 +
>> 2 files changed, 78 insertions(+)
>>
>> diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
>> index 21b196c..7aaf7d3 100644
>> --- a/drivers/hid/hid-input.c
>> +++ b/drivers/hid/hid-input.c
>> @@ -1198,6 +1198,67 @@ static struct hid_input *hidinput_allocate(struct
>> hid_device *hid)
>> return hidinput;
>> }
>>
>> +static bool hidinput_has_been_populated(struct hid_input *hidinput)
>> +{
>> + int i;
>> + bool r = 0;
>> +
>> + for (i = 0; i < BITS_TO_LONGS(EV_CNT); i++)
>> + r = r || hidinput->input->evbit[i];
>
> I believe there is a bit count method that will do this for you (weight).
>
Actually, weight does not work here. evbit[] is an array of long, and we
still need to check if each field of this array is not null.
Thus, the following can be used (r being a long here):
r |= hidinput->input->evbit[i];
Cheers,
Benjamin
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