I'm new to ubuntu and my Asus X555LA brought me here.

The fn + (brightness up/brightness down) is not working, i did some search and what i tried till now is modifying grub file from etc\default

GRUB_CMDLINE_LINUX="acpi_osi=linux acpi_backlight=vendor"

To mention fn+brightness works in BIOS and i use ubuntu 15.10 but the same problem is in 14.04 or 14.10.

Now is there any other solution? And if there is please can you explain it on baby steps :-?



      product: Intel(R) Core(TM) i3-5010U CPU @ 2.10GHz
      vendor: Intel Corp.
      physical id: 1
      bus info: cpu@0
      size: 2100MHz
      capacity: 2100MHz
      width: 64 bits


         description: VGA compatible controller
         product: Broadwell-U Integrated Graphics
         vendor: Intel Corporation
         physical id: 2
         bus info: pci@0000:00:02.0
         version: 09
         width: 64 bits
         clock: 33MHz
         capabilities: msi pm vga_controller bus_master cap_list rom
         configuration: driver=i915 latency=0
         resources: irq:48 memory:b1000000-b1ffffff memory:c0000000-cfffffff ioport:4000(size=64)

PS: I did found xbacklight app with custom keys, but the fact that fn on brightness doesn't work bugs me.


ls /sys/class/backlight

asus-nb-wmi intel_backlight

Thanks, Kim

  • Please edit your question and add output of ls /sys/class/backlight – Pilot6 Nov 14 '15 at 16:34
  • Did you try boot parameter acpi_osi=? Without any "Linux", etc. – Pilot6 Nov 30 '15 at 15:03
  • Yes did that, i found out that my fn and brightness keys are not bound to any event... i did some dig and there's a way to do it but it's to complicated, so first i need to get used with ubuntu then maybe ill try fix that :-? – Cravenica Dec 2 '15 at 12:05

If you can use xbacklight, then you need to point the default control to intel_backlight.


sudo -H gedit /usr/share/X11/xorg.conf.d/20-intel.conf

and paste this text to gedit:

Section "Device"
    Identifier "Card0"
    Driver "intel"
    Option "Backlight" "intel_backlight"
    BusID "PCI:0:2:0"

then reboot.

  • Still not working, with this one i can't even modify the brightness from system settings or xbacklight. I did update grub every time... – Cravenica Nov 12 '15 at 22:05
  • I updated the answer. – Pilot6 Nov 14 '15 at 16:41
  • still nothing ... does my grub need to look like this or im doning something wrong ? GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=intel_backlight" GRUB_CMDLINE_LINUX="" – Cravenica Nov 14 '15 at 21:03
  • It is wrong to put this to linux cmdline. – Pilot6 Nov 14 '15 at 21:10
  • ok, i changed it back to quiet splash then reboot, and still nothing :-s the fn+brightness is not working. i'm still using normal key bind to use the xbacklight app – Cravenica Nov 14 '15 at 21:31

I have asus and i had same problem since 15.04 this how i fix it

install latest intel driver from http://01.org/linuxgraphics

then edit grub as below

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi= acpi acpi_backlight=vendor GRUB_CMDLINE_LINUX="noprompt persistent"

  • i tried it and still not working. the weird part is that there's no event on brightness key's and I think that's the main problem, but i don't know how to link those key to an event – Cravenica Jan 11 '16 at 11:24
  • I tested brightness Fn keys with command acpi_listen and there was no event, after did above steps it's working – user1998978 Jan 16 '16 at 5:48

FYI: After upgrading to 17.04 this issue no longer occurred.

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