Dell E7440, same problem on 14.04: very quick to change brightness using intel_backlight command, but hardward keys (Fn-Up/Down) pause the computer briefly.
Thanks to instruction from user Toz (http://ubuntuforums.org/showthread.php?t=2208278), the fix requires both "acpi_backlight=vendor" kernel param and creating the /usr/share/X11/xorg.conf.d/20-intel.conf file:
-------------------
Section "Device"
Identifier "card0"
Driver "intel"
Option "Backlight" "intel_backlight"
BusID "PCI:0:2:0"
EndSection
-------------------
Dell E7440, same problem on 14.04: very quick to change brightness using intel_backlight command, but hardward keys (Fn-Up/Down) pause the computer briefly.
Thanks to instruction from user Toz (http:// ubuntuforums. org/showthread. php?t=2208278), the fix requires both "acpi_backlight =vendor" kernel param and creating the /usr/share/ X11/xorg. conf.d/ 20-intel. conf file:
-------------------
Section "Device"
Identifier "card0"
Driver "intel"
Option "Backlight" "intel_backlight"
BusID "PCI:0:2:0"
EndSection
-------------------