>>> >>> With regards to partial MT devices, if the device provides a single >>> valued property, such as pressure and tool type for synaptics, it may >>> only be provided through the traditional property semantics, i.e. >>> ABS_PRESSURE and BTN_TOOL_*. If the device provides multiple values for >>> a property, then ABS_MT_* types may be used as well to provide up to two >>> values, though the client should understand there's no direct >>> correlation between the slot's coordinates and the property. I could see >>> this being used to provide info on multiple tool types or a high and low >>> pressure. >>> >>> Enforcing the above behaviour provides even more information about the >>> capabilities of the device based solely on the evdev codes published. >> >> >> Looks good, but I do not think we need to formalize all possibilities here, only >> the usage of MT data for bounding rectangle and ST data for finger count. >> Referring to the patch just sent: whenever INPUT_PROP_SEMI_MT is true, this >> behavior is expected. In the event of new odd hardware, the combination of a new >> property quirk and a documented recipe should do the trick. > > Would you feel comfortable stating the above in less concrete terms, as > sort of a best practices guide? I'd like to know for this specific case > if you agree beyond ST finger count data, or if you feel we should do > something else like always provide as much data as possible in MT > properties? It's a real corner case, and I don't care too much one way > or another. I just don't want synaptics implemented one way, elantech > another, etc. A driver can still choose to report ABS_MT_PRESSURE for instance, in which case it is assumed to make sense for individual fingers/corners. For semi-mt devices, it seems reasonable to go to the ST variants to collect information not provided via the MT protocol. I see no immediate reason to specify beyond that point. 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
