I installed a backported kernel as per the instructions to installnewerkernel. The kernel installed but wouldn’t load on reboot after installation. I removed the backported kernel and deactivated the backport repo. Then I installed one version older kernel than the kernel default that was already installed, as a second kernel for backup.
After I had tried to boot on the backported kernel, I rebooted and booted with the kernel-default that was already installed before the newer backported kernel installation. I don’t know why, but now the video projector projects the desktop, but at the wrong scale. Only an enlarged portion of the entire laptop screen is displayed on the projection screen by the video projector. I went to settings> display and monitor, and the video projector (hdmi1) is not detected. I can’t reduce the scale of the projected screen in order to display the correct scale of projection, so that the entire laptop screen is displayed.
It appears that the i915 driver for the Xe graphics is correct.