Xfce Forum

Corneus

Member

Registered: 2018-02-19

Posts: 3

Changing screen brightness does'nt work (fn keys)

Hello,
I would like to change it, even the pop-up  will show up but it does'nt change the brightness. I'm using the fn keys.
Power manager is installed.

Desktop: Xfce 4.12.4
           Distro: Debian GNU/Linux buster/sid
Device: laptop System: LENOVO product: 3260EDU v: ThinkPad Edge E535 serial: N/A
           Mobo: LENOVO model: 3260EDU v: Win8 Pro DPK TPG serial: N/A
           UEFI [Legacy]: LENOVO v: HHET75WW (2.08 ) date: 10/24/2012

Thank you.

ToZ

Administrator

From: Canada

Registered: 2011-06-02

Posts: 11,482

Re: Changing screen brightness does'nt work (fn keys)

Hello and welcome.

Can you provide some more info?

1. Your video card(s):

lspci -vnk | grep -A15 VGA

2. Your backlight interfaces:

ls /sys/class/backlight/

3. Your current kernel parameters:

cat /proc/cmdline

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Corneus

Member

Registered: 2018-02-19

Posts: 3

Re: Changing screen brightness does'nt work (fn keys)

Thanks mate.

1.
00:01.0 0300: 1002:9992 (prog-if 00 [VGA controller])
    Subsystem: 17aa:5100
    Flags: bus master, fast devsel, latency 0, IRQ 11
    Memory at e0000000 (32-bit, prefetchable) [size=256M]
    I/O ports at 3000 [size=256]
    Memory at f0300000 (32-bit, non-prefetchable) [size=256K]
    [virtual] Expansion ROM at 000c0000 [disabled] [size=128K]
    Capabilities: [50] Power Management version 3
    Capabilities: [58] Express Root Complex Integrated Endpoint, MSI 00
    Capabilities: [a0] MSI: Enable- Count=1/1 Maskable- 64bit+
    Capabilities: [100] Vendor Specific Information: ID=0001 Rev=1 Len=010 <?>
    Kernel modules: radeon

00:01.1 0403: 1002:9902
    Subsystem: 17aa:5100
    Flags: bus master, fast devsel, latency 0, IRQ 33

2.
acpi_video0

3.
BOOT_IMAGE=/boot/vmlinuz-4.14.0-3-amd64 root=UUID=a4de39df-f25d-42cb-ba2a-c04464bbaa95 ro quiet

ToZ

Administrator

From: Canada

Registered: 2011-06-02

Posts: 11,482

Re: Changing screen brightness does'nt work (fn keys)

A few things to try:

1. Does xbacklight work?

xbacklight -dec 50

2. Does the following command work:

echo 1 | sudo tee /sys/class/backlight/acpi_video0/brightness

3. Kernel parameters to try:
- thinkpad-acpi.brightness_enable=1 acpi_backlight=vendor
- acpi_backlight=vendor
- acpi_osi=

More info on debugging backlight issues can be found here. If you are able to control the backlight by a method other than the power manager or fn keys, then we can look deeper into the power manager. Otherwise, its a kernel issue and needs to be addressed at that level.

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Corneus

Member

Registered: 2018-02-19

Posts: 3

Re: Changing screen brightness does'nt work (fn keys)

1.
No outputs have backlight property

2.
It does not work.

3.
I tried all of them, nothing changed. The first and second just disabled the brightness pop-up.

There is no way to control the brightness, neither through the power manager or shell.

Yea I already thought about it. I started with the stable on this laptop and then went to testing. The old kernel was deleted.I think I was able to control the brightness on stable, but I'm not sure. It's been a while.