Description:

xorg-xbacklight 1.2.0-1 is not working as expected. With previous version of xorg-xbacklight (1.1.2.3 or so) I could change the backlight of my laptop without any problems. Now when I run xorg-xbacklight nothing happens (no error message, exit status 0).

I have no problem changing backlight using the following methods:

1) echo 3 > /sys/class/backlight/acpi_video0/brightness

when run as root (maximum brightness is 7 on my laptop, minimum = 0)

2) xrandr --output LVDS --set BACKLIGHT 3

[siema@laptop ~]$ xrandr --verbose | grep -i backlight
BACKLIGHT: 3 (0x00000003) range: (0,7)


I downloaded the source for the previous version of xorg-xbacklight from here (it came up when I searched for it with google):

http://cgit.freedesktop.org/xorg/app/xbacklight/plain/xbacklight.c?id=d52f81e43da29d94122d62c1b1be34946960033c

I understand that this is some older version but seems to be working for me. When searching for any differences (apart from those in the source code) I found that it's linked against libXrandr, whereas the newer one is not:

[siema@laptop ~]$ pacman -Q xorg-xbacklight
xorg-xbacklight 1.2.0-1

[siema@laptop ~]$ ldd /usr/bin/xbacklight
linux-vdso.so.1 (0x00007fff279ff000)
libxcb-randr.so.0 => /usr/lib/libxcb-randr.so.0 (0x00007fa824a73000)
libxcb-util.so.1 => /usr/lib/libxcb-util.so.1 (0x00007fa82486e000)
libxcb.so.1 => /usr/lib/libxcb.so.1 (0x00007fa82464f000)
libc.so.6 => /usr/lib/libc.so.6 (0x00007fa8242a8000)
libXau.so.6 => /usr/lib/libXau.so.6 (0x00007fa8240a4000)
libXdmcp.so.6 => /usr/lib/libXdmcp.so.6 (0x00007fa823e9e000)
/lib/ld-linux-x86-64.so.2 (0x00007fa824c7e000)

The one I build from source code (I did that manually with gcc `pkg-config --cflags --libs xrandr x11` xbacklight.c -o xbacklight):

[siema@laptop ~]$ ldd ./xbacklight
linux-vdso.so.1 (0x00007fff3d7ff000)
libXrandr.so.2 => /usr/lib/libXrandr.so.2 (0x00007fd8911ff000)
libX11.so.6 => /usr/lib/libX11.so.6 (0x00007fd890ec6000)
libc.so.6 => /usr/lib/libc.so.6 (0x00007fd890b1f000)
libXext.so.6 => /usr/lib/libXext.so.6 (0x00007fd89090c000)
libXrender.so.1 => /usr/lib/libXrender.so.1 (0x00007fd890701000)
libxcb.so.1 => /usr/lib/libxcb.so.1 (0x00007fd8904e2000)
libdl.so.2 => /usr/lib/libdl.so.2 (0x00007fd8902de000)
/lib/ld-linux-x86-64.so.2 (0x00007fd891409000)
libXau.so.6 => /usr/lib/libXau.so.6 (0x00007fd8900da000)
libXdmcp.so.6 => /usr/lib/libXdmcp.so.6 (0x00007fd88fed4000)


I attached the working file in case the one referenced by the link I gave eariler changes.