Hi On Tue, Nov 4, 2014 at 4:51 AM, Peter Hutterer <[email protected]> wrote: > On Mon, Nov 03, 2014 at 11:56:59AM +0100, David Herrmann wrote: >> I haven't spent much time thinking it through, but so far I'd prefer a >> solid, but basic, heuristic to guess the DPI and then use hwdb for >> anything that doesn't fit. This allows us to change the heuristic at >> any time and we don't have to introduce any APIs. We can even ship the >> hwdb files with libinput. > > tbh, I don't think heuristics will work. there is no reference point and > when you're looking at relative motion you can't tell if a delta of > 10 means the pointer has moved a large distance at low-res or a small > distance at high-res.
I was more talking about the MIN/MAX values reported by the device. I assumed that high-dpi devices just reported higher precision for the same interval as low-dpi devices. But as your data shows, this turns out to be not true... what a bummer! > Anyway, for some data: > I recorded my Logitech G500s here with three different dpi settings (400, > 800, 2000) and a MS Comfort Optical Mouse 3000 (1000 dpi). A couple of > interesting things: regardless of dpi, virtually all events are within [-3, > +3] dx/dy and there's nothing over 10. Exception here is the MS mouse which > goes up to 78 for a delta, for reasons I can't explain yet. Interesting. This is probably to throttle HID throughput and use report-on-change, instead of continuous-reporting. Anyway, if you want, I can come up with a hwdb format to retrieve DPI settings. Just lemme know what you want to match on for the devices. Thanks David _______________________________________________ wayland-devel mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/wayland-devel
