OSX dithering - Help wanted

Well, as said above, the kext might not do its work, although it loads.

After three full days of testing, I can say that I got as tired as before. The same feeling of overworked eyes and head/eye strain/pressure. And I'm pretty sure it's the iMac screen, because I managed to relax somewhat by playing on the iPad

This only shows itself after prolonged periods of intensive work, so I can spend 1-2 hours at the screen quite easily.

In the process, I also switched off Gamma Control for a while and returned from HD-709 color profile to the standard iMac profile, and after a short time my eyes started burning. This makes me believe that apart from macOS dithering, the iMac screen has brightness issues.

annv After three full days of testing, I can say that I got as tired as before. The same feeling of overworked eyes and head/eye strain/pressure.

Ahh thanks for testing @annv, I'm hoping that the kext will lead us to further developments down the line so it's not the end of the world. I'm hoping to have some more news about it soon.

The developer of the kext to disable temporal dithering on MacOS sent me a very interesting reply. Sadly he does not have the time to be able to work with us on this, but he has given some interesting pointers on how we could proceed with another developer, with the caveat that Apple are moving changing kext's to exist more into the userspace than the kernel as has been mentioned above.

• Crucially, they were only able to develop the kext because of a tight relationship between the company he was working for and ATI/AMD, who guided them on how to tweak the right parameters to disable the dithering. They didn't speak to Apple at all, this was done entirely with ATI/AMD as temporal dithering exists at the GPU driver level in MacOS - it's an abstraction the kernel has no interest in handling directly, it just tells the GPU/driver what colour it was where in the framebuffer

• There is a hardware check as a 'dongle' for the kext. This could be bypassed by patching the kext to USB vendor ID that the kext looks for to verify hardware. I think this is where we should focus our attention as once bypassed it will at the very least allow us to rule out temporal dithering as the root cause of our issue in MacOS.

If anyone feels like they can do this or knows someone who can then get in touch and I will forward on everything that was said. Failing that we can crowdfund the development cost from this forum I'm sure.

si_edgey

I'd be happy to take part in croudfunding.

I do not have any particular developers in mind, but I would contact people whose apps I use and like. I also wonder if hackintoshers can be knowledgeable in this.

erwin

I have downloaded the HD-709 profile here: https://www.youtube.com/watch?v=YwjLuUR51gE

There is a link under the video.

There is also a description of what it does on the website: https://www.sebastianleitner.com As this person says: go to "DCP Course and ebook". He also says that it's the only profile that does not go through ColorSync utility. He is a video producer and this is the way he makes all the video editing programs on Mac to show the same colors.

I've put it more in detail in this thread: https://ledstrain.org/d/768-colorsync-on-macos-what-is-this-could-it-be-a-culprit

Yes, Gamma Control is the app on the App Store by Michel Fortin, but it costs USD 18.99 in my country. I've bought it from the developer directly on his website though: https://michelf.ca/projects/gamma-control/ This way, it has a trial period and (AFAIR) a better upgrade policy.

erwin Could you please give a link to the v.2.0.0 BT.709 profile?

annv

Thanks for all the links. I'll give Gamma Control a try and if I like it I'll buy it directly from the developer. Apple has become such a patronising company with their design choices, both software and hardware, that sending any more money in their direction even just in the form of commision is not on the agenda.

This is the link to the profile I found: http://www.color.org/rec709.xalter Very washed-out compared to anything else I've tried, and consequently very easy on the eye. Excellent.

Incidentally, I just tried loading the Amulet Hotkey kext on Catalina, and I had the same identical message you had. Not sure if I'll go all the way with the hackintosh workaround you mentioned, mainly because it seems that after managing to load the kext there was no benefit in your case. Please correct me if I'm wrong.

erwin

Thank you for the link.

It seems that Amulet kext does not have an effect for me. However, after all my tweaks I have very mild symptoms and I need to spend a few hours with the text to feel tired. (But they start at some point for sure.)

si_edgey

Thank you so much for sharing the kext injector.

I managed to load it in a very straightforward way by using KextBeast https://www.tonymacx86.com/resources/kextbeast-2-0-2.399/ It couldn't be simpler than that, the only downside is that you need to register before being able to download the app.

annv

One thing I noticed after loading the kext is the following: when the login screen appears after power-up, after say a couple of seconds it's like if a layer is removed off the screen. The picture appears slightly less defined, but it still looks great and it's like it a layer of extra contrast has been removed. And this is before logging into any profile, hence I don't expect the screen settings of any specific profile to have an effect there at the start-up page.

Another thing I noticed after injecting the kext is that, when the Apple logo appears after power-up and the bar is loading, it would stop for a split second halfway through when I was on 10.15.2, and now that I am on 10.15.5 it gliches for a split second at the equivalent point.

On a side note, 10.15.5 looks slightly different from 10.15.2 to me, there is a bit more contrast everywhere I'd say. Other than that I have no issues, but then again I've always been fine with the iMac except that one month in summer 2018 and that single day this week. Sure, there is still way too much light everywhere on the screen and my old LG G2 is way more relaxing to read things on, but at the same time no more nausea, headache, dizziness, etc.

After using KextBeast, ahkinject.kext is present in two folders within my iMac::
/Library/Extensions
/Library/StagedExtensions/Library/Extensions

si_edgey

What I could do is to unload the kext and check whether the behaviour described in the message above goes away. I just need to investigate how to unload the kext the right way, since I'm new to all this.

That's interesting that you're noticing some difference at the boot-up screen, comforting to know that it is doing something. After I spoke to the original developer he confirmed that it does do exactly what we want it to, but it checks for hardware belonging to the company that it was developed for - perhaps it does this after you log in. I'm guessing your MacOS desktop doesn't look any different?

We just need to find a way to bypass this check!

erwin Hey Erwin, how do we fix this? Do I need to get someone to change the code? If so, what kind of coder?

ryans

I'm afraid I have long since abandoned Macbook laptops - they just won't work for me, and I also believe that Apple is intending to deprecate the KEXT system in favour of System Extensions, which would mean a rewrite of the code.

The main issue is that the KEXT checks for the Amulet hardware being attached by USB - so you could reverse engineer the code to bypass this check but I'm not entirely sure who to approach to do that. The key info the developer gave me was:

1. Crucially, they were only able to develop the kext because of a tight relationship between the company he was working for and ATI/AMD, who guided them on how to tweak the right parameters to disable the dithering. They didn't speak to Apple at all, this was done entirely with ATI/AMD as temporal dithering exists at the GPU driver level in MacOS - it's an abstraction the kernel has no interest in handling directly, it just tells the GPU/driver what colour it was where in the framebuffer
2. There is a hardware check as a 'dongle' for the kext. This could be bypassed by patching the kext to USB vendor ID that the kext looks for to verify hardware. I think this is where we should focus our attention as once bypassed it will at the very least allow us to rule out temporal dithering as the root cause of our issue in MacOS.

Hope that helps somehow!

si_edgey is there any progress on this?

@JTL we're you ever able to program a solution? I'd love to message you for more info. I've tried to inject the AHK kext, but it was no help - I assume because of the hardware/software check. Desperate to find a solution on disabling dithering on a 2019 MBP