Ubuntu

brightness keys stopped working

Asked by Pär Johansson

I was running "dpkg --configure -a" a few days ago. Now, I noticed that the keys F11 and F12 no longer adjust brightness.
No percentage is displayed on the screen and the screen clearly does not change brightness.
It has worked without a problem the last 3 years.

My computer is a "Dell Inspiron 15-3552". It is laptop.

uname -a
Linux par-Inspiron-15-3552 3.13.0-165-generic #215-Ubuntu SMP Wed Jan 16 11:46:47 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

sudo lspci -v | grep -A10 VGA
00:02.0 VGA compatible controller: Intel Corporation Device 22b1 (rev 21) (prog-if 00 [VGA controller])
        Subsystem: Dell Device 06ac
        Flags: bus master, fast devsel, latency 0, IRQ 11
        Memory at 90000000 (64-bit, non-prefetchable) [size=16M]
        Memory at 80000000 (64-bit, prefetchable) [size=256M]
        I/O ports at f000 [size=64]
        Expansion ROM at <unassigned> [disabled]
        Capabilities: [d0] Power Management version 2
        Capabilities: [90] MSI: Enable- Count=1/1 Maskable- 64bit-
        Capabilities: [b0] Vendor Specific Information: Len=07 <?>

I also noticed that:

ll /sys/class/backlight/
totalt 0
drwxr-xr-x 2 root root 0 mar 6 18:18 ./
drwxr-xr-x 54 root root 0 mar 6 17:43 ../

I can assure everyone that the laptop is not equipped with a CRT monitor.

I was wondering if this theoretically could have any connection to the two other issues i have:
#678914
#678910

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actionparsnip (andrew-woodhead666) said : 		#1

I'm seeing a lot of this:

https://itsfoss.com/fix-brightness-ubuntu-1310/

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Pär Johansson (paer-johansson) said : 		#2

No, it did not solve the problem.

Step 1:
ls /sys/class/backlight/

(that is, the dir is empty)

Step 2: Since lspci indicates intel, I created the file as shown in the link You provided. Content of file:
cat /usr/share/X11/xorg.conf.d/20-intel.conf
Section "Device"
        Identifier "card0"
        Driver "intel"
        Option "Backlight" "intel_backlight"
        BusID "PCI:0:2:0"
EndSection

I logged out and the screen went black for a long time (is it supposed to do that?).
Logged in again, but I still cannot change brightness.

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Launchpad Janitor (janitor) said : 		#3

This question was expired because it remained in the 'Open' state without activity for the last 15 days.