Re: [Linuxwacom-discuss] Intuos4 and pointer jitter

[Alexia D. <ale...@gm...>]

On Tuesday 22 December 2009 20:24:44 SHIRAKAWA Akira wrote:

> 
> Today I tried Running Ubuntu 9.10 64 bit on Windows 7 64 bit under a
> VirtualBox virtual machine with USB support. My Intuos4 tablet works
> correctly, except for the same jitter problem that is still there,
> virtualized on my Windows machine.
>
> As this doesn't occur under Windows in native mode (the pointer is
> perfectly stable) on the very same pc, I'm now almost certain that it's
> a Linux driver / software fault of some sort.
 
Your result actually proves, that there is nothing wrong with linuxwacom 
drivers because for virtualbox USB they are bypassed completely and the 
windows driver handles raw usb data. The part that I believe differs for you 
between native and virtual is the linux USB controller driver for you 
particular chipset. There seems to be some sort of a problem on that level. a 
bug or an utilization difference that adds noise. I  dont know USB architecture 
too well, but If I was you I would test the tablet with an external powered 
hub in case there is a problem with providing power and perhaps try to force 
the driver to use an older 1.1 USB protocol.

Most esoteric thing I can come up with is that you are using a CRT monitor 
that is used at different frequency&resolution between OSes and generates 
disturbing RF noise.

-- Alexia