Michael Poole wrote: [...] > > How would the slot number for a contact be chosen? The device driver determines how to use the slots. The driver calls input_mt_slot(dev, slot), sends the data for the slot, picks another slot, and repeats. > If the kernel makes > that assignment, what should a "slot" correspond to from a computer > user's perspective? "Set[s] of identified sources" is a little vague: > Does it mean contacts from one hand, contacts in one displayed window > (assuming the touch surface is a screen), or something else? (I assume > it would not duplicate the blob or tracking IDs already defined for MT > events.) The slot is only used for data communication. Think of the slot as a combined, unique identifier. For example, imagine a device driver dealing with contacts labeled with both a USER_ID and a TRACKING_ID. The driver assigns every active (USER_ID, TRACKING_ID) contact to a specific slot, and uses it to communicate all changes to that contact. When the contact is destroyed (for instance by sending a zero ABS_MT_PRESSURE on that slot), the slot is free to be used for another contact. > It seems like those would be important aspects of the protocol > to document in Documentation/input/multi-touch-protocol.txt -- > otherwise, driver implementers or application developers might get it > wrong. Certainly. Cheers, 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
