Hi there,
$ lspci | grep VGA 00:02.0 VGA compatible controller: Intel Corporation ValleyView Gen7 (rev 0e)
$ sudo lspci -v -s 00:02 00:02.0 VGA compatible controller: Intel Corporation ValleyView Gen7 (rev 0e) (prog-if 00 [VGA controller]) Subsystem: Hewlett-Packard Company Device 2213 Flags: bus master, fast devsel, latency 0, IRQ 107 Memory at 90000000 (32-bit, non-prefetchable) [size=4M] Memory at 80000000 (32-bit, prefetchable) [size=256M] I/O ports at 3050 [size=8] Expansion ROM at <unassigned> [disabled] Capabilities: [d0] Power Management version 2 Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit- Capabilities: [b0] Vendor Specific Information: Len=07 <?> Kernel driver in use: i915
=> requires the following to make brightness control keys work as expected
$ cat /etc/modprobe.d/i915.conf options i915 invert_brightness=1
tested on ubuntu 14.04 (with added xorg conf below)
$ cat /usr/share/X11/xorg.conf.d/20-intel.conf Section "Device" Identifier "card0" Driver "intel" Option "Backlight" "intel_backlight" BusID "PCI:0:2:0" EndSection
Note that the same brightness inversion happened also on ubuntu 14.10 (vanilla install, no xorg conf required)
Cheers, Olivier.