When running with my HDMI screen and the laptop screen (with brightness at 0 because i don’t need it in that configuration), both with the unified screen option, I have good performances.
But when I disable my laptop screen to just output to my HDMI screen, performance are abysmal.
I try that to lower the energetic consumption (there is a slight increase when outputs are unified, and I though a slight decrease of performance as well).
On the bright side with 515: the HDMI screen is working fine, but the laptop screen will go black with the dash → “_” on the upper left side of the screen.
The laptop screen is perfectly working during the boot and halt phase. But coming at the login prompt, it stays black.
The HDMI screen works perfectly when the laptop one doesn’t.
If the hdmi screen is unplugged, the laptop screen will keep being black with the underscore top left…
In the display configuration, the laptop screen is not detected.