cvs commit: src/sys/isa psm.c

[Brian F. Feldman]

Alfred Perlstein <alfred at FreeBSD.org> wrote:
> * Eivind Eklund <eivind at FreeBSD.org> [031211 04:08] wrote:
> > On Thu, Dec 11, 2003 at 03:28:11AM -0800, Alfred Perlstein wrote:
> > >   Log:
> > >   Significantly reduce the "jitter" that is typical for PS/2 mice
> > >   when using a KVM.
> > [...]
> > >   
> > >   The actual solution that appears to offer the best clamping of
> > >   jitter is to buffer the mouse packets if we've not seen mouse
> > >   activity for more than .5 seconds.  Then waiting to flush that data
> > >   for 1/20th of a second.  If within that 20th of a second we get any
> > >   packets that do fail the weak test we drop the entire queue and
> > >   back off accepting data from the mouse for 2 seconds and then repeat
> > >   the whole deal.
> > 
> > Have you tested this with enough high speed interactive games?  50ms 
> > (1/20s) is three to four frames, and quite a lot of delaying input.  
> > There are a number of types of games that require faster response than 
> > this.  I'm not entirely sure how it influences most mouse-run games - I 
> > know that at least some 2D fighting games with joystick absolutely 
> > required 1-frame (20ms) response on 50Hz displays.   
> 
> There is only a delay if the mouse has been idle for .5 seconds,
> otherwise the reaction is immediate.  I guess we could tune that
> up to 2 seconds, it's also tunable via sysctls.  Feedback, testing
> and tweaking are encouraged, this is -current afterall. :)

I can't imagine that most people that are playing these sorts of games use a 
KVM switch, and as such probably have no need for a PS/2 mouse and would 
want to use a USB mouse instead.  Still, the default should probably be 
several seconds at least; when I used a KVM I don't think I ever managed to 
switch from and back to one of the computers in less than a few seconds :)

-- 
Brian Fundakowski Feldman                           \'[ FreeBSD ]''''''''''\
  <> green at FreeBSD.org                               \  The Power to Serve! \
 Opinions expressed are my own.                       \,,,,,,,,,,,,,,,,,,,,,,\