Hi Marc, I'm experiencing similar behaviour on my Dell Latitude E6530: updating the brightness blocks (mouse) input and is very slow.
Adding 'acpi_backlight=vendor' to the kernel parameters has helped a lot on my system to make the brightness updates less slow. It's still slower than it used to be, but has improved since I've added this parameter. Regards, Rik -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org