Re: Linux USB HID should ignore values outside LogicalMinimum/Maximum range

[Denilson Figueiredo de SÃ]

On Mon, 24 Oct 2011 14:39:31 -0200, Denilson Figueiredo de SÃ wrote:
> On Mon, Oct 24, 2011 at 14:24, Chris Friesen wrote:
> > On 10/22/2011 05:42 AM, Denilson Figueiredo de SÃ wrote:
> >
> > > It may even happen to send an out-of-range value for one axis, but a
> > > valid value for another axis. The code should be prepared for that
> > > (ignore one, but keep the other).
> >
> > In this case what should be used for the "invalid" axis value?  The  
> > previous value?

> I haven't tested that on Windows (yet), so I don't know how it
> behaves. If I test it, I'll post my results here.

I've modified the firmware of my device to do some more tests. I've  
modified it to send invalid values in X axis, but keep Y axis with valid  
values.

In Linux, the pointer moved to the right-most position of the screen  
(which is consistent with the behavior I previously described), not  
ignoring the out-of-range value.

In Windows, the pointer moved to the left-most position of the screen. It  
means Windows can't send a movement of only one axis, and fills the other  
axis with zero when receiving an invalid value. This behavior doesn't seem  
very helpful.


If anyone cares, this was the firmware modification for this test:
https://bitbucket.org/denilsonsa/atmega8-magnetometer-usb-mouse/changeset/31027323fa0b

--
Denilson Figueiredo de SÃ
Rio de Janeiro - Brasil
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