Controlling display backlight manualy
Yes, it is completely safe. Echoing into
/sys
(or/proc
) does not overwrite kernel configuration directly, it runs a kernel userspace function which do validate the input.xrandr
/xbacklight
actually performs pretty much that (as far as I know).Since it worked before I bet that
xbacklight
is simply finding the wrong backlight directory in/sys/class/backlight
. I suppose there is more than one directory in there, right?I'm not 100% sure of it but
xrandr
/xbacklight
will choose theacpi
directories (e.g./sys/class/backlight/acpi_video0
) before trying something like/sys/class/backlight/intel_backlight/
(which is the one your current driver is creating/using).(I'm not 100% sure but found a decent reference on arch wiki that more-or-less confirms it)
To force
xbacklight
to use the right directory you can add the following toxorg.conf
(or preferably drop a*.conf
file in/etc/X11/xorg.conf.d/
) with the following section:Section "Device" Identifier "Card0" Driver "intel" Option "Backlight" " intel_backlight" EndSection
(Disclaimer: I have not tested it since I do not have an intel card, if this section does not work you might try substituting
"Card0"
for"Screen0"
)