On Sun, May 6, 2012 at 9:03 PM, Henrik Rydberg <rydberg@xxxxxxxxxxx> wrote: > Hi, > >> Win8 devices are required to present the feature "Maximum Contact Number". >> If the current value is 0, then, the driver can get the actual supported >> contact count by seeing the logical_max. > > And for win7, it is zero? Well, the truth is that the Win8 specification formally describes the values here. And to get the certification, hardware makers have to put the right value in logical_max. TBH, I don't care that much now with win7 devices. Most of them are a piece of crap (not true dual fingers, problems in hid reports descriptors, etc...), but they just work (we made the necessary things). With the introduction of Win8, hardware makers will have to *certify* their devices, and thus, the Win8 driver is much less tolerant. I really think that we are going to see more and more win8 devices, whereas win7 devices will fade out. I had to add this patch because I have a win8 device that has the value associated to this field at 0, and it's the first I saw with this behavior. Cheers, Benjamin > >> >> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxx> >> --- >> drivers/hid/hid-multitouch.c | 2 ++ >> 1 files changed, 2 insertions(+), 0 deletions(-) >> >> diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c >> index c6ffb05..e205d1e 100644 >> --- a/drivers/hid/hid-multitouch.c >> +++ b/drivers/hid/hid-multitouch.c >> @@ -265,6 +265,8 @@ static void mt_feature_mapping(struct hid_device *hdev, >> case HID_DG_CONTACTMAX: >> td->maxcontact_report_id = field->report->id; >> td->maxcontacts = field->value[0]; >> + if (!td->maxcontacts) >> + td->maxcontacts = field->logical_maximum; >> if (td->mtclass.maxcontacts) >> /* check if the maxcontacts is given by the class */ >> td->maxcontacts = td->mtclass.maxcontacts; >> -- >> 1.7.7.6 >> > > Thanks, > Henrik -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
