Hi @susanne and thanks for your query. I am afraid that whilst the Tobii Tracker 4C under the Pro SDK will work with Linux, this is not applicable to the EyeX as most of the information processing in this older hardware is done via software (as opposed to onboard in the case of the 4C) installed on the PC and this was never ported (at least publically) to Linux.
Certainly, you can use the EyeX with Python and Pro SDK under Windows, but I am afraid that due to the constraints of the software used, that a “no screen” option is not something that is generally supported either with the Tech Range of Trackers. For this advanced setup purpose, we have the Tobii Pro range of trackers that are designed to allow for this.
All that being said, if you were able to work under Windows with the Device you could calibrate on screen and then simply replace the screen with an appropriately sized stimulus, but such a setup would of course not be optimal. You would however at least have the 3D Gaze Vector exposed for analysis.
If you need to use Linux and in particular a screenless setup, then a Tobii Pro Solution would be the most appropriate. I was curious to see what GazeSDK solution you were referring to? Perhaps there is some workaround that we can offer. Apologies for the disappointing news.