On Thu, Nov 22, 2018 at 04:34:05PM +1000, Peter Hutterer wrote: > Windows uses a magic number of 120 for a wheel click. High-resolution > scroll wheels are supposed to use a fraction of 120 to signal smaller > scroll steps. This is implemented by the Resolution Multiplier in the > device itself. I scooped a dirty old MS Wireless Mobile Mouse 4000 out of a mate's bin and it breaks this assumption. The resolution multiplier is 16 which isn't an integer fraction of 120. Real multiplier is 7.5. The device sends hi-res values of 4, so it should end up as REL_WHEEL_HI_RES 30. We are getting 28 instead which doesn't add up to a nice 120. Basic assumption: MS uses something other than plain 120 internally. The choices we have now are: - use 1200 or 12000 internally and divide by 10 before sending the final value - just make the evdev API use 1200 or 12000 and let userspace deal with it. much simpler. Any suggestions/comments? Cheers, Peter
