Non-linear backlight brightness on Acer Aspire 5 (AMD) since recent kernel update – 0% brighter than 1-5%

[brucew]

@ixe

1% is sufficiently dark, but 0% is significantly brighter

Then there’s your fix. Run it at 1% instead.

@ixe

It may have the same cause

I’m the guy who asked the question on Arch Forums. It’s an AMD issue not an Arch or Manjaro one. They’ve been mucking about in their kernal patches without considering the impact on laptop users.

Around the same time–6.12 to 6.13–one of their patches raised the CPU idle speed from barest minimum to something else. I mention this since I see your CPU idle speeds are higher than barest minimum, which may also increase power use and reduce battery runtimes.

See this thread for that fix:

AMD idle speed higher with kernel 6.13 than with 6.12

After the Feb 4 testing branch update, which went just fine across the board, I also tried out the 6.13.1-2 kernel update. On my antique Intel laptop there are no issues. On both my AMD machines, (Zen3 desktop and Zen4 laptop), both using tuned 2.25.1-1 (balanced power profile) for power management, the CPU idle speed jumps under 6.13 as compared to 6.12 with no other changes–simply making the appropriate choice in the grub menu. On the desktop, idle speed jumps from 550 MHz to 1737 MHz. The…

There’s another thread opened here today about how to get AMD to backport these and other fixes:

Timeline for amdgpu backports into 6.12 stable kernel?

There have recently been issued some patches for various race conditions in the amdgpu driver to fix the frequent ‘page flip timed out’ errors/screen freezes like drm/amd/display: fix dmub access race condition drm/amdgpu/vcn3: read back register after written and I’m asking myself how I can find out when those arrive in 6.12. I’m not even sure which kernel they have been added to (6.16/6.17rc) as of right now. I don’t want to bother the amdgpu driver folks in their gitlab with such a beginn…

EDIT: And it seems that, potentially, there;s more fun to come:

AMD Posts Latest Linux Patches For Improving S5 Power Consumption