Xfce Forum

almahdi

Member

Registered: 2020-07-04

Posts: 125

Why cannot get back to the brightness level after blank/screen off

Laptop brightness defaults to be the lowest level /0, but every time after blank screen /screen off (also this I need difference explanation), it won't be able to get back to the lowest level of brightness as the display restoration can only be done by set its level next to the lowest one, ie increase the brightness (mine is Fn F3), then it'd be immediately set back lower than it (Fn F2) to be the lowest but without any effect.
How to solve this?

Last edited by almahdi (2020-07-06 03:02:43)

ToZ

Administrator

From: Canada

Registered: 2011-06-02

Posts: 11,023

Re: Why cannot get back to the brightness level after blank/screen off

What is the make and model of your laptop?

What graphics card do you have and which driver are you using?

lspci -v | grep -A12 VGA

Which backlight interfaces do you have?

ls /sys/class/backlight

This is most likely a system/kernel issue and not and Xfce issue.

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almahdi

Member

Registered: 2020-07-04

Posts: 125

Re: Why cannot get back to the brightness level after blank/screen off

You bet
Always echo 2 similar lines error, at very first Manjaro-20 start, sort of:

Failed to load/save backlight brightness on acpi0 ...

here PCI specs.
VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Kaveri [Radeon R6 Graphics] (prog-if 00 [VGA controller])
    DeviceName: Onboard IGD
    Subsystem: Hewlett-Packard Company Kaveri [Radeon R6 Graphics]
    Flags: bus master, fast devsel, latency 0, IRQ 52
    Memory at a0000000 (64-bit, prefetchable) [size=256M]
    Memory at c0800000 (64-bit, prefetchable) [size=8M]
    I/O ports at f000 [size=256]
    Memory at feb00000 (32-bit, non-prefetchable) [size=256K]
    Expansion ROM at 000c0000 [disabled] [size=128K]
    Capabilities: <access denied>
    Kernel driver in use: radeon
    Kernel modules: radeon, amdgpu

$ /sys/class/backlight
radeon_bl0

Last edited by almahdi (2020-07-06 03:13:25)

ToZ

Administrator

From: Canada

Registered: 2011-06-02

Posts: 11,023

Re: Why cannot get back to the brightness level after blank/screen off

Failed to load/save backlight brightness on acpi0 ...

Perhaps this (https://bbs.archlinux.org/viewtopic.php?id=211967) will help.

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