[Bug 32840] Mouse input regression caused by changes in GetTickCount64

[wine-bugs at winehq.org]

http://bugs.winehq.org/show_bug.cgi?id=32840

--- Comment #3 from Jeff Cook <jeff at deserettechnology.com> 2013-01-30 13:53:10 CST ---
We had some adventures with this in #winehackers early this morning.

It seems the likely cause is that something is using get_tick_count() in
server/request.c or a similar function that would have a large variance from
the system-provided monotonic timer, which will typically reflect the given
uptime of the machine in milliseconds regardless of when the wine server
starts, and that somewhere a comparison is occurring that causes an underflow
or something.

We haven't been able to pinpoint the cause of mouse inversion in some menus,
but investigation appears to clear user32/input.c (though there is a bug here
where the hardcoded 100ms server update interval is useless with the monotonic
timer because the difference from last_change, which is a low number, is always
going to be much higher than 100; practically, the only effect of this bug is
probably some wasted CPU cycles) and similar obvious mouse-related suspects.

Did some light tinkering with pdh.dll but I don't think there's anything really
there. GetTickCount64 is rarely called directly, but its output is fed to
GetTickCount, which then gets cast/truncated into a DWORD.

Still not much of a clue as to why axes are getting inverted, but it definitely
seems the transition to monotonic GetTickCount*() functionality hasn't been
thoroughly tested. It appears there are several places where the comparison of
monotonic and non-monotonic timers, while theoretically not necessarily
problematic, may result in conflicts or unexpected behavior, which may or may
not manifest in applications as bugs (and in this case, obviously one does). I
almost want to suggest that the change gets rolled back if these can't all be
ferreted out and we can't confirm that every comparison is from the same type
of timer, or that in cases where timers with different originations are
compared, we ensure there is no potential issue.

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