Older versions of the X server would (implicitly) allow one to do, for example xset m 1/8 1 to disable mouse acceleration. The '1/8' could be tweaked to change the mouse sensitivity under these non-accelerated conditions. In the latest versions of the X server, the code has been (significantly?) cleaned up. Unfortunately, the above no longer works properly. Try it; the mouse pointer will not move unless the mouse is moved very rapidly. It would be nice if there was a (driver-independent?) way to set the mouse sensitivity. The old way was consistent, in the sense that (1) xset m 2 1 doubles the mouse speed but still disables acceleration, and that (2) xset m 1/8 1 decreases the mouse speed by some amount. I have no idea how to re-implement the old model. The current code appears to be correct; it multiplies the mouse delta by 1/8, and for small movements, the mouse delta can be (1, 1); (1/8)*(1, 1) = (0, 0), and so this results in no pointer motion. Can this be "fixed" so that even without acceleration, one can use fractional values like '1/8' to modify the mouse sensitivity?
I forgot to mention that (1) still works in the new model. Thus xset m 2 1 will currently "double" the pointer speed, as expected.
I believe I have found the source of the issue. include/inputstr.h: int dxremaind, dyremaind; /* for acceleration */ Those should be floats. I'm going to recompile and test that, of course...
Indeed, changing include/inputstr.h: int dxremaind, dyremaind; /* for acceleration */ to include/inputstr.h: float dxremaind, dyremaind; /* for acceleration */ fixes the issue.
This seems to be fixed in newer versions.
False alarm. It's still broken. I'm not sure what caused me to think that it was fixed. I swear I saw inputstr.h no longer exist, with the code fixed in another file or something... I'll attach a patch in a minute.
Created attachment 13806 [details] [review] Patch to fix mouse acceleration
*** Bug 14205 has been marked as a duplicate of this bug. ***
(In reply to comment #6) > Created an attachment (id=13806) [details] > Patch to fix mouse acceleration > this patch breaks the ABI, so we can't put it in before 1.5.
Was commited to git master as 0050165a67bb462e0bf644a11644ad9d587c62bb.
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