absolute coordinate mouse support

Alex Williamson alex.williamson at hp.com
Wed Sep 21 11:07:17 PDT 2005

On Wed, 2005-09-21 at 13:50 -0400, James Cloos wrote:
> >>>>> "Alex" == Alex Williamson <alex.williamson at hp.com> writes:
> Alex> an tell me to switch to something besides the X "mouse" driver
> Perhaps evdev does what you want.

   Yes, I was just looking into that, thanks for mentioning it.  The
evdev driver apparently ignores absolute data at the moment, but I think
I can add that without too much problem.  Probably missing just because
absolute coordinate devices aren't nearly as common.

   The only hard issue that I can think of so far with adding absolute
motion support is determining the min/max values.  These are part of the
standard USB HID info, but there's no way to get that from the Linux
evdev interface AFAIK.  I'm thinking there are probably two ways to
handle this:

     1. Dynamically determining these values based on the motion of the
     2. Driver options in the xorg.conf file indicating min/max x/y

I think the 1st option is most critical even though it essentially
requires the user to sweep the screen with the mouse before it becomes
very accurate.  At least the device becomes usable fairly easily.  The
2nd option is for the user that restarts X enough that they care to go
lookup the values.  Other suggestions?  Thanks,


Alex Williamson                             HP Linux & Open Source Lab

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