linux-kernel - Re: [PATCH v2 07/11] HID: hid-multitouch: move ALWAYS

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Date:	Tue, 30 Oct 2012 11:19:21 +0100
From:	Benjamin Tissoires <benjamin.tissoires@...il.com>
To:	Henrik Rydberg <rydberg@...omail.se>
Cc:	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Jiri Kosina <jkosina@...e.cz>,
	Stephane Chatty <chatty@...c.fr>, linux-input@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 07/11] HID: hid-multitouch: move ALWAYS_VALID quirk check

On Mon, Oct 29, 2012 at 11:16 PM, Henrik Rydberg <rydberg@...omail.se> wrote:
> Hi Benjamin,
>
>> Win 8 device specification changed the requirements for the hid usages
>> of the multitouch devices. Now InRange is optional and must be only
>> used when the device supports hovering.
>>
>> This ensures that the quirk ALWAYS_VALID is taken into account and
>> also ensures its precedence over the other VALID* quirks.
>>
>> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@...il.com>
>> ---
>>  drivers/hid/hid-multitouch.c | 6 ++----
>>  1 file changed, 2 insertions(+), 4 deletions(-)
>
> Since we seem to never actually reset td, this seems equivalent,
> unless some device added ALWAYS VALID by mistake, even if INRANGE is
> not part of the report descriptor.

Yes, it is equivalent for Win7 devices. The field InRange was
mandatory, and currently, nobody mixed ALWAYS_VALID with other quirks.
But now, InRange is optional, and device not supporting hovering
should not use it, so it's mandatory to move it at a place we can be
sure it will be taken into account.

>
>> diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
>> index 000c979..43bd8e8 100644
>> --- a/drivers/hid/hid-multitouch.c
>> +++ b/drivers/hid/hid-multitouch.c
>> @@ -506,7 +506,7 @@ static int mt_compute_slot(struct mt_device *td, struct input_dev *input)
>>   */
>>  static void mt_complete_slot(struct mt_device *td, struct input_dev *input)
>>  {
>> -     if (td->curvalid) {
>> +     if (td->curvalid || td->mtclass.quirks & MT_QUIRK_ALWAYS_VALID) {
>
> I found at least one presence of this construct in the kernel, but I
> think the overwhelming majority use parenthesis.

oops, I was really angry against parenthesis in this patch series :)

Cheers,
Benjamin

>
>>               int slotnum = mt_compute_slot(td, input);
>>               struct mt_slot *s = &td->curdata;
>>
>> @@ -561,9 +561,7 @@ static int mt_event(struct hid_device *hid, struct hid_field *field,
>>       if (hid->claimed & HID_CLAIMED_INPUT) {
>>               switch (usage->hid) {
>>               case HID_DG_INRANGE:
>> -                     if (quirks & MT_QUIRK_ALWAYS_VALID)
>> -                             td->curvalid = true;
>> -                     else if (quirks & MT_QUIRK_VALID_IS_INRANGE)
>> +                     if (quirks & MT_QUIRK_VALID_IS_INRANGE)
>>                               td->curvalid = value;
>>                       break;
>>               case HID_DG_TIPSWITCH:
>> --
>> 1.7.11.7
>>
>
> Thanks,
> Henrik
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