I have been trying to figure out how to get palm detection working on my new Dell XPS 13 9343. It has a Windows Precision Touchpad (PTP) compliant touchpad; I think it's a Synaptics rebrand. DLL0665:01 06CB:76AD UNKNOWN; that 06CB definitely indicates it's Synaptics under there. I've been trying to figure out if it's not sending information along that could be used to determine if a touch is intentional or unintentional or if the Linux drivers - either kernel or userspace - just don't support what it's sending. PTP devices must send at least "confidence", which is used to indicate that a touch is not a finger. They may also send width and height which could be used for detection. It doesn't look like confidence is supported by Linux currently. In trying to figure this out, I looked at the HID descriptor and noticed that it's not reporting itself as a PTP but rather as a mouse. This is actually as expected for an PTP compliant device which hasn't been initialized fully - according to https://msdn.microsoft.com/en-us/library/windows/hardware/dn467314(v=vs.85).aspx devices are supposed to use the Mouse Collection for input reporting until the input mode is set to touchpad, after which they're supposed to switch to the Windows Precision Touchpad Collection. It looks like the hid-multitouch driver generally doesn't set the input mode on devices to MT_INPUTMODE_TOUCHPAD (0x3). By default it sets it to MT_INPUTMODE_TOUCHSCREEN (0x2) in mt_probe. It does also set it to MT_INPUTMODE_TOUCHAD (0x3) in mt_touch_input_mapping, though I haven't traced through to see if that actually gets written out to the device or is just used by the driver to determine how to interpret various events. Have I missed something? Is it actually being initialized to PTP mode and rdesc just isn't being updated? That would probably lead to misinterpreting some events since the event collections are very different, so it seems unlikely. Is there some condition under which it does get initialized to PTP mode? If I'm right and this mode just isn't supported currently, is anyone working on this functionality? I'd rather not duplicate effort. Cheers, Michael -- 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
