[Bug 84561] [ivb] Intel backlight does not adjust, but only turns on/off in kernel 3.16 on Samsung 880Z5E laptop

[bugzilla-daemon at bugzilla.kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=84561

Laszlo KREKACS <laszlo.krekacs.list at gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |laszlo.krekacs.list at gmail.c
                   |                            |om

--- Comment #7 from Laszlo KREKACS <laszlo.krekacs.list at gmail.com> ---
I have a Samsung np870z5e-x01hu model laptop, so almost identical  to the
reporter, and the bug is exactly the same on my side.
(my videocard is intelhd4000 + Radeon HD 8870)

I created an ubuntu bug about it, with all(?) the info attached here:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1380824

(I'm also cross-referencing the two bug, for convenience).

My linux kernel version is:
Linux lasam 3.16.0-21-generic #28-Ubuntu SMP Mon Oct 6 16:00:43 UTC 2014 x86_64
x86_64 x86_64 GNU/Linux

I tried all the below combination (one-by-one, reboot between each try, and
check with cat /proc/cmdline):
$ vi /etc/default/grub
in line 11:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video.use_native_backlight=1"
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video.use_native_backlight=0"
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_backlight=vendor"
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video.use_bios_initial_backlight=0"
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=Linux"
$ update-grub


None of it worked. Also neither the xorg.conf trick works.

Only the sofware workaround (gamma adjustement) works, but it is not a
solution, only workaround:
xrandr --output LVDS-0 --brightness 0.5

Question to the original reporter:
What is your bios version? (sudo dmidecode -s bios-version)

Mine is P02ADH.

-- 
You are receiving this mail because:
You are on the CC list for the bug.
You are the assignee for the bug.