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e996

Member

Registered: 2015-10-01

Posts: 9

[SOLVED] brightness, sleep buttons not working on thinkpad t420

my brightness controls (fn+home and fn+end) as well as the sleep button (fn+f4) have stopped working correctly on my t420 with arch and openbox.
the brightness can still go up and down, but the lowest settings just turn off the backlight completely instead of getting dimmer. i can still bring it back up from there though
the sleep button does nothing.
i have no idea what i've done to cause this, as they were all working fine one day and not the next.
acpi_listen sees all of the keys just fine.
if i log in as root (who has nothing installed) they all work perfectly, i suspect because of thinkpad-acpi included in the kernel.
i tried adding

acpi_osi="!Windows 2012"

as well as

acpi_backlight=vendor

,

acpi_backlight=none

and

acpi_osi=Linux

to my boot parameters, but none of them fixed it.
xbacklight gives an error of "No outputs have backlight property," and im not entirely sure how i would fix that.

raising and lowering the brightness does not change /sys/class/backlight/acpi_video0/actual_brightness, which seems to be locked at 5 (although, again, if i'm logged in as root this does work correctly). it does change /sys/class/backlight/intel_backlight/actual_brightness, but not in the correct increments. it skips from 443 down to zero.

any help would be appreciated!

Last edited by e996 (2016-08-13 22:27:39)

e996

Member

Registered: 2015-10-01

Posts: 9

Re: [SOLVED] brightness, sleep buttons not working on thinkpad t420

additionally, completely uninstalling and then reinstalling tp_smapi, now version 0.42, has not fixed the problem, although i'm not sure tp_smapi is to blame.
/sys/class/backlight/acpi_video0/actual_brightness is also now stuck at 1, for some reason.....

e996

Member

Registered: 2015-10-01

Posts: 9

Re: [SOLVED] brightness, sleep buttons not working on thinkpad t420

issue fixed by reinstalling thinkfan from the AUR, not sure what caused it in the first place.