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linux-surface
Thumbs not detected
My thumbs are not getting detected in any situation in SP4. All other fingers work perfectly well otherwise. Checking the code, https://github.com/linux-surface/iptsd/blob/91bebe4a1247a56b9ca062265d7648d2dcd099d2/src/touch-processing.c#L78 this line is probably the culprit. Removing the [vx / vy > 1.8] condition fixes the thumbs not being detected, and everything else works as expected. I'm not sure what is the math behind that formula, but it didn't work for me. Hope it helps
I'm getting this both for my thumbs and any other finger if i dont tap vertically on the SP6
Same thing happens on Windows, but the threshold is much larger so it works well with thumbs. I am thinking the specific condition of vx / vy > 1.8 is not true in most cases for me, disabling thumb detection. @OmegaRogue could you please change the code and compile iptsd to check if it restores expected thumb detection for you? In my case thumbs are working correctly after changing that line.
Also maybe someone can clarify what that condition means? I think it has something to do with eigenvalues and variance but not sure.
Ill try it out as soon as i get the chance, but something i also noticed is that it rejects my fingers but doesn't properly reject my actual palm, especially when its on the edge of the screen
@OmegaRogue what do you mean exactly with palm rejection? There is a mode called BlockOnPalm that disables touch input in the area near the stylus. This is disabled by default and can be enabled by setting that mode in /etc/ipts.conf. If you mean you are getting random touches on the screen, specially when holding it with a hand you may try increasing the TouchThreshold to 15 in the same config file, it helped me with a lot of ghost clicks.
I'd say iptsd is pretty functional in SP4, with the following issues:
- Thumbs not getting detected(fixable by increasing thresholds in touch-processing.c)
- Only 2 fingers max get detected by screen, and pressing with a 3rd one disables the other 2.
- Touch locations cannot be too close together or they stop working
I was able to detect the last 2 issues by comparing touch inputs on https://tecagile.com/online-touch-screen-test between windows and linux, so I'm not sure if it is firefox-linux's fault or iptsd. Also I get no info about touch area in that same page, not that it is important though.
Hands on screen not being detected as touches is what i understand under palm rejection