Ubuntu interpid hotplug breaks any 3dconnexion device

Questions and answers about 3Dconnexion devices on UNIX and Linux.

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Ubuntu interpid hotplug breaks any 3dconnexion device

Post by pyalot » Thu Jan 29, 2009 4:10 am

The new hotplug support attempts to add this device as a pointer, therefore any other event source (evdev, usbfs) does not get any events anymore and it is effectively broken.

Subscribe/Comment on this bug https://bugs.launchpad.net/ubuntu/+sour ... ug/297264/

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Post by crobl » Thu Feb 12, 2009 8:42 am

Hello pyalot,

the issue you describe with our devices is actually not a bug. Linux or better evdev handles our devices absolutely the way it should be.

Our devices register themselves as relative devices. This has historical reasons and may change with future products from 3Dconnexion.
Since the devices are known to the system to be relative devices, only the relative structure members contain values. Although the outputted values are absolute, the structure members for absolute values are not set.
This is correct behaviour of evdev.

A drawback of this is that the min/max values are not set in the event interface structure. The minimum/maximum value for the axes are +/-512.
Btw. You can also find these values in the HID descriptor.

Best regards,
Christian Robl

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