quo

Interestingly the THC actually has two identical DMA receive interfaces. The second one sends HID data, so I thought maybe the first would allow access to the raw data somehow,...

So here's the driver: https://github.com/quo/ithc-linux And a slightly modified iptsd to go with it: https://github.com/quo/iptsd You're probably right that a zero-copy interface isn't worth it. Mapping the DMA ringbuffer into...

> Isn't the multitouch data already HID wrapped? Not really. I mean, sure, they've added a report ID byte at the front, but that's it. The report descriptor just says...

I had a quick look at the pen data on a SP7+. The most interesting data seems to be in the DFT window packets with length 1548. I did not...

The smaller DFT window packets have the same format, but contain fewer rows. The "a" value is the number of rows per coordinate. When the pen is touching the screen,...

I was mostly just looking at the data without thinking too much about what's going on at the hardware level. From skimming the papers, it looks like they have horizontal...

> Assuming the pen sends some fixed single-frequency signal (at least one frequency for position) and the wires receive that, then you could just check for where reception of that...

I've added experimental SP7/SP7+ pen support to my iptsd fork: https://github.com/quo/iptsd It will probably still need a lot of tuning, and the processing could be improved in various ways. And...

Thank you, should be fixed now.

The multitouch processing is from the libqzed branch of the official iptsd, I'm not really familiar with that part of the code yet. I recommend opening an issue at https://github.com/linux-surface/iptsd/issues