A Sensible Rant: ABM is Worse than Cancer

I just upgraded my Framework 13 (Fedora 42) from an Intel 11th gen board to an AMD 7840U, to get better battery life and improve performance and DEAR GOD WHAT HAVE YOU DONE TO THE SCREEN?!

There are a bunch of things wrong by default, at least five things.

First off, the colors are simultaneously too-bright, washed out, and low contrast; and text is washed out and low contrast. I know the screen is supposed to look better than this. I saw it looking better just a few minutes ago. The last time I saw a display this fucked up (can we swear here?) it was on a $200 laptop. Did the … profile… get lost? Maybe I’ll go to KDE’s Display Preferences. No matter how much I screw around with the color profile, “Color accuracy” (is this something to do with software vs. hardware rendering of something or other?), “sRGB color intensity”, “brightness”, and “Extended Dynamic Range”, it still looks like trash.

I can’t even see a difference between “efficiency” and “accuracy”. Neither of these is anywhere near accurate and – well, now the display is frozen. That’s a kernel oops on new hardware. Hopefully it’s a software issue. I guess. Is that better or worse? Let’s power the laptop off and try again.

Oh look at that. If I change from “Power Save” to “Balanced”, suddenly the display looks reasonable. At least it looks close to right. Wait, I remember reading vicarious frustration! All I have to do is type “AMD” and a bunch of profanity into a search engine… and sure enough, “Vari-Bright”. Who even – that sounds like a name for the paint I’d drink to start thinking this feature was a good idea to turn on silently by default.

Imagine one day, my car starts driving like crap. I take it to a mechanic, and he goes “oh yeah, I snuck into your garage and removed 2nd and 3rd from your transmission,” exhibiting a toothy grin. Considering homicide, I stare at his overalls. “Don’t worry,” he says, “the parts are in your trunk if you want them.”

Ok, so, the thing for me to do, is to leave this ABM thing enabled, but make sure it’s always turned off except in extreme circumstances, the two times a year when I am desperate enough to behold its effects. Hold on. I could almost… Yes. My browser window is growing dimmer and brighter without me changing the backlight settings. It is doing this of its own volition, on the fringes of my perception. Into my field of vision, creeping incongruity, white or whiter?

All of the Internet stuff is talking about Power Profiles Daemon. Which Fedora helpfully replaced a few versions ago with, I guess, tuned. But I don’t know that yet. More emissive, less emissive. As tendrils of darkness likewise creep, splay, writhe, impinging on the edges of my sight…

“tuned-adm”, is this even the right thing? It doesn’t seem to have any settings I can set with it, only these randomly named profiles. If I’m taking this long, I’d better just use the kernel setting to disable ABM entirely.

The sun’s moved into the room a bit more, so I try to adjust the brightness upward. The brightness on the laptop does not change. First it was changing by itself. Now it is not changing when I press the buttons. Oh, 1% through 8% is all the same backlight level. Someone broke the brightness controls. The map is misshapen. 1% is no longer 1%. 8% is 0%. Is 100%?

I change the brightness to 100%, to check. It sears, it blinds. I think it might only be 94%. I watch the search page, without dark mode. It is lunch time, but I have already eaten my retinas.

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Yeah turn off automatic screen brightness or the equivalent on KDE. I hate it on phones and I hate it on laptops, if desktops had it … I would hate it there as well. I am perfectly capable of changing brightness manually when I actually need to…any additional circus fun you might be encountering could easily be AMD specific, don’t know…have not gone down that particular road yet.

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When it’s humorous as in your case, I think everyone agrees to let it slide.

I sincerely sympathize but I also chuckled immensely reading this rant. Not to fear, I also amuse those around me when I rant in the way you are doing now.

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FWIW I use abm level 3 and I don’t even notice it, so its free extra battery life for me.

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You can’t really blame FW for the auto-brightness problems. It in things like GNOME to blame for that.
The display panel itself can be programmed with about 65536 levels of backlight brightness. Gnome, in its flawed wisdom, only uses 100 levels, so when it changes level, your eyes really notice. If gnome had been sensible, and used more subtle and slower more gradual changes in level, that the display can do, it would be much less obvious when it changed brightness.

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Your situation is a useful warning – I’d not run into this problem.

Not to minimise your current experience and frustration, and I hope you’re free from cancer, but F__k Cancer.

K3n.

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I wasn’t sure, but I made myself laugh. :wink:

That’s… hmm, cool. I don’t know if I should say, “turn it off and see how much better things look” or if that’s bad advice. I’m still using the OG Framework 13 display, and I find myself consciously enjoying looking at it reasonably often.

I often wonder how much we humans are affected by sensory things within our conscious experience, but beneath the threshold of awareness. I have to think a lot.

I’m with you, entirely in the camp of, all brightness controls should be explicit and have a consistent meaning. I mean broadly, even on say, a MacBook, dimming the display in a low power mode is just stupid. If I wanted / could tolerate a dimmer display in a given environment, I would have already set it dimmer. Changing the settings just… ignores user choices and makes things inconsistent. It doesn’t belong in power configuration.

I haven’t noticed it since setting amdgpu.abmlevel=0. I can’t say for sure, but I think it was part of ABM, rather than part of some environmental autoadjustment. I don’t think I even have the light sensor hooked up to anything software-wise.

The brightness settings curve being wrong with manual adjustment… seems to be some AMD thing, I guess, maybe because I’m on the original display. I switched to performance mode, and it’s the same. Seems to hit what used to be 0% at 8%, and then that’s the floor. My old 5% or 10% seems to now be around 40-50%. I don’t have any way of judging 100% because I don’t usually work in direct sunlight.

To not joke, I think ABM, distinct from brightness settings, is a fantastic option that should be disabled by default, but visibly available in whichever Desktop environment’s Power Settings, no matter the profile. I expect my computer to run slower – quantitative differences – in Power Save, but I don’t expect implicit qualitative differences. Tolerance for semi-busted colors/contrasts is orthogonal to tolerance for reduced performance. The default should always be off. Would people’s intuition be better if we were talking about audio quality?

At the same time, I run in Power Save the majority of the time, because I want all the battery life I can get with low effort, all of the time. I never have extra energy that I’m not greedily holding onto. On my Framework 16, I’ll even play games in Power Save in order to have the fans noticeably quieter or avoid draining the battery while it’s plugged in, if the games aren’t too demanding (or even sometimes if they are but aren’t twitchy).

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I just spent the past 5 days with it turned off. Initially I noticed the screen was slightly brighter, but that is to be expected because ABM lowers the backlight brightness. Otherwise, the colors looked the same to me. After 5 days, I re-enabled it and everything still looks the same except for noticing that the backlight is slightly dimmer (as expected).

Its worth noting that I am only using ABM. I’m not doing any sort of ambient light auto-adjustment, so my backlight doesn’t auto-adjust if I go between a dark room or a sunny field.

You might want to take a look at /sys/class/backlight/amdgpu_bl0. Inside that folder is:

  • brightness which is the level you set the backlight to.
  • actual_brightness which is the level ABM adjusted your backlight to.
  • max_brightness is the max value you can set for brightness (so on my machine, brightness is set to 85 and max_brightness is 255, so I set my backlight to 33%, but ABM adjusts the actual_brightness lower than that)

They might help you nail down what is going on.

Otherwise, you might just be particularly sensitive? If you browse eink forums, you’ll find that they gush about how eink saves their eyes and how regular monitors cause eye strain. If you browse lighting forums you’ll find people (including a good friend of mine) who complain about flicker in LED lights and go to great lengths to find flicker-free bulbs. Both of those groups are a small minority of the population. The general public is not impacted by these issues at all. You might be the same but for backlights/colors.

Now you tempt me to turn the thing back on. I’m actually a bit curious.

Could be, probably likely. I’m not sure what passes for insensitive. In the old days, I used to be astonished that my parents could stand to watch 4:3 TV signals on 16:9 televisions. A character would cock his head, you’d watch the change in the distortion in shape, look to the other people in the room with you, and they’d not seem to react.

Now that you mention it, I do occasionally see that LED flicker in the periphery of my vision, with some of them. I can see how it would be deeply annoying at a certain point.

:grin: … and since you brought it up, those eink people are completely right about the superiority of non-emissive displays and paper. I don’t know about eyestrain, but it’s nicer.


With amdgpu.abmlevel=0, and PPD set to “performance”, and a scale of 0-255, it’s basically at 1% backlight between 1% and 7%, then linear up to 20%, then on this reasonable-seeming curve toward 100%. (The individual percentage steps will alternate between 2 and 4 actual_brightness in places, which seems odd, but it probably doesn’t matter.)

Overall, doesn’t seem quite right.

percentage brightness actual_brightness
0 1 0
7 18 1
9 23 2
10 26 3
11 28 4
20 51 14
30 77 31
40 102 53
50 128 79
60 153 106
70 179 140
80 204 174
90 230 212
100 255 255

One other thought: with it enabled, do you know if it’s at “level 3” or “level 1”? I didn’t notice a major difference with it enabled and Power Profiles Daemon set to Balanced mode. The big difference was in Power Save mode.