Bug 500643

Summary: Using Fn-brightness keys only works properly on external keyboard and has long delay with laptop keyboard
Product: [Plasma] plasmashell Reporter: slartibart70
Component: Power management & brightnessAssignee: Plasma Bugs List <plasma-bugs-null>
Status: REPORTED ---    
Severity: normal CC: ilikefoss, jpetso, kde, kde, kdedev, nate
Priority: NOR    
Version First Reported In: 6.3.90   
Target Milestone: 1.0   
Platform: Fedora RPMs   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description slartibart70 2025-02-23 22:59:42 UTC
I have a p14s gen4 amd laptop. The laptop keyboard has a Fn-key and brightness keys on F5/F6.
Using Fn-with F1 to F4 (speaker on/off, volume down/up/mute mic) works flawlessly.

Pressing Fn-F5 or Fn-F6 (brightness of laptop screen down/up) works only with a very large delay (~20sec) until the OSD appears and the brightness changes

I also have an external keyboard (logi ergo K860) sporting a Fn-key and brightness controls.
If i press Fn-F1 or Fn-F2 (brightness down/up) on the k860 this works instantly.

This wasn't a problem before plasma6, there both brightness-controls worked in the same instant way.
Comment 1 slartibart70 2025-02-23 22:59:58 UTC
Operating System: Fedora Linux 41
KDE Plasma Version: 6.3.80
KDE Frameworks Version: 6.12.0
Qt Version: 6.8.2
Kernel Version: 6.13.3-201.fc41.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 PRO 7840U w/ Radeon 780M Graphics
Memory: 58,5 GiB of RAM
Graphics Processor: AMD Radeon 780M
Manufacturer: LENOVO
Product Name: 21K5000JGE
System Version: ThinkPad P14s Gen 4
Comment 2 Nate Graham 2025-02-24 17:04:31 UTC
Works as expected for me with:
- 2020 Lenovo ThinkPad X1 Yoga gen 4
- 2024 HP Pavilion 14 plus

Both when alone, or connected to an external keyboard.
Comment 3 TraceyC 2025-02-24 19:56:26 UTC
I'm also not able to reproduce on git-master on a Lenovo Flex, which has an AMD Ryzen processor and AMD integrated GPU
I tested with the built-in keyboard
Comment 4 John 2025-02-24 20:06:24 UTC
I also cannot reproduce on Debian 13 (Trixie) - unstable repository, with:

SOFTWARE/OS VERSIONS
Linux/KDE Plasma:
KDE Plasma Version: 6.3.0
KDE Frameworks Version: 6.11.0
Qt Version: 6.7.2
Kernel Version: 6.12.16-amd64 (64-bit)
Mesa  Version: 25.0.0-1
Graphics Platform: Wayland


HARDWARE SPECIFICATIONS
Hardware: Laptop Dell Inspiron 5770 (17" 1080p@60Hz screen)
CPU: Intel® Core™ i5-8250U CPU @ 1.60GHz
GPU 1: Mesa Intel® UHD Graphics 620 (main, Vulkan capable)
GPU 2: AMD Radeon R5 M465 Series
RAM: 8 GiB (7.7 GiB usable)

Tested just with the built-in keyboard too.
Comment 5 slartibart70 2025-02-24 20:15:03 UTC
well, this is currently a problem with this specific laptop - even without any attachments (keyboard or thunderbolt devices)
Just changing the brightness with Fn-F5/6 e.g. running on batteries has effect only after this 20sec delay.
Setting other Fn-Fxx keys with global hotkey functions do work immediately

I can also confirm that other laptops (t470p/intel+nvidia or old t420/intel only) don't have this problem.

Any logs i can provide?
Comment 6 Nate Graham 2025-02-24 20:17:26 UTC Comment hidden (spam)
Comment 7 Nate Graham 2025-02-24 20:17:49 UTC
It sounds like this may be a hardware, firmware, or driver problem on that machine.
Comment 8 slartibart70 2025-04-07 08:36:12 UTC
there was a firmware upgrade for the p14s in the meantime, so i'm up-to-date now
still no change to the behaviour.
(ext. keyboard FN-changes as well as brightness slider for the laptop-display update the brightness instantly)
Comment 9 Nate Graham 2025-08-13 22:21:53 UTC
Still happening in Plasma 6.4.4?
Comment 10 slartibart70 2025-08-19 19:16:01 UTC
Operating System: Fedora Linux 42
KDE Plasma Version: 6.4.80
KDE Frameworks Version: 6.18.0
Qt Version: 6.9.1
Kernel Version: 6.15.10-200.fc42.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 PRO 7840U w/ Radeon 780M Graphics
Memory: 64 GiB of RAM (58.5 GiB usable)
Graphics Processor: AMD Radeon 780M Graphics

newest firmware, current 6.5-dev updates... yes, it's still happening.
The audio-function keys on the laptop (fn-f1/f2/f3/f4) work instantly, the brightness-controls (fn-f5/f6) only with a long delay