The enter and down arrow keys work randomly, either with the BIOS or with Ubuntu 15.10, and I suspect the drivers of the graphics card. Here is a history of the facts:
- New laptop with cubuntu, everything worked.
- Installation of Ubuntu 15.04, no problems with the keys.
- Upgrade to Ubuntu 15.10, first dysfunction of enter and down arrow keys, either with the BIOS or with Ubuntu
- After an update, the keys are working again regularly.
- After connecting a video projector to the VGA port, new malfunction of both keys.
- New installation of Ubuntu 15.10. Currently both keys working always episodically, either with the BIOS or with Ubuntu, either using Nvidia or Intel GPU. For the Nvidia GPU, I tested the nvidia-352, the nvidia-352-updates and the X.org driver, and for Intel GPU I tested the intel-microcode and the free drivers.
Is it a problem with the drivers of the Nvidia card? How can I solve this malfunction?