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The journey to controlling external monitors on M1 Macs

alinpanaitiu.com

61–70 of 188 posts

Re: The journey to controlling external monitors on M1 Macs

#63
Although I'm not interested at all in brightness control and the different technologies you described, I really enjoyed reading your post. Your way of combining talking about technical issues with your personal life and challenges (your company job, having a side project along your day job, the winter cold near your house, etc.) made it possible for me to enjoy reading a post about something completely unrelated to me (DDC, etc.) Nice job.

Re: The journey to controlling external monitors on M1 Macs

#66

Apple seems to be making a lot of display related things difficult lately. This, and Display Stream Compression are two. Just as high refresh and HDR were becoming really mainstream, Big Sur completely broke what was working flawlessly in Catalina (and it has not been fixed as of either 11.5, or the Monterey betas so far - and by completely broke, I mean does not work, at all, for anybody, not just 'some edge case').…

If your livelihood isn't dependent on that kind of a display, personally, I would try to avoid falling into their trap. I'd call it anti-competitive to have previously supported an industry standard, only to then remove that support and push their product as the only way to achieve an equivalent to that standard. I'm not saying the ProDisplay XDR isn't a good screen, or even overpriced in the class of displays it liv…

Precisely. I'd be very happy to have a ProDisplay. I may even buy it for the aesthetics (well, above and beyond everything else - I'm also a professional photographer). But as you say, it's more the attitude. I'm guessing whatever proprietary stuff they've done to drive the XDR at 6K in HDR isn't compatible with DSC, and there's little interest in fixing it.

Re: The journey to controlling external monitors on M1 Macs

#67
post #23

Earlier quoted context omitted.

Unfortunately no, Gamma doesnt reduce the power consumption of the LED backlight of the monitor. It may in fact increase power use a bit because rendering black pixels needs more energy to excite the crystals. I haven't contacted Apple because I don't think they are interested in implementing such a thing really. I've written more about why I think that here: https://lobste.rs/s/2zajeu/journey_controlling_external_mo…

I have a monitor that has "eco" mode, reducing the brightness. Is that a different DCC command or are they implementing a similar gamma reduction? If not could an eco mode be called, if indeed it is a industry wide standard for reducing energy usage?

Brightness is literally just a backlight power level (pretty much), so gamma and eco mode are a completely separate concept. Frankly I have no idea what eco mode means, but I wouldn't be surprised if it's just brightness * 0.75 + contrast * 1.25.

Re: The journey to controlling external monitors on M1 Macs

#68

Earlier quoted context omitted.

They can. This entire article is about how they implemented it on M1 macs. Did you read it?

It doesn't sound like it works very well

That it works at all is a major improvement, and the Raspberry Pi method is worth having as well; I've been working on something very similar since I got my M1 Mini and found ddcctl and Lunar unable to work there, but got little further than building the light sensor before other projects took priority - I expect I'll probably finish this one around the equinox.

My work laptop, an Intel Mac, displays to and controls brightness on the same monitor, but I've been using ddcctl with a trivial wrapper script much more than Lunar of late. (Kinda feel a little bad about that, what with the author of Lunar having taken the time to give me tech support on a weird corner case here on HN a while back.) Still going to buy a license and, if I can find a way, set up a recurring donation. This kind of work deserves support.

Re: The journey to controlling external monitors on M1 Macs

#69

It's appalling that something like this necessary.

Controlling external displays via DDC was never supported, and only works even on Intel Macs via a "private," undocumented API. It's neither appalling nor even surprising that this wasn't prioritized for the M1 kernel, and it is likewise reasonable that some more reverse engineering would be required.

Re: The journey to controlling external monitors on M1 Macs

#70
post #51
post #6

Earlier quoted context omitted.

There is https://www.ddcutil.com/ It has a command line utility and a qt GUI. Unfortunately the GUI is a bit convoluted, because it exposes every option that you can change on the monitor. I once almost bricked my LG monitor, because I accidentally locked the hardware buttons on my monitor, via an undocumented manufacturer specific option. For gnome there is https://extensions.gnome.org/extension/2645/brightness-cont…

> Unfortunately the GUI is a bit convoluted, because it exposes every option that you can change Wow, color me surprised. That doesn't sound like a desktop Linux app at all :) >I once almost bricked my LG monitor, because I accidentally locked the hardware buttons on my monitor, via an undocumented manufacturer specific option. Reminds of the good old days of late 90s / early 2000s desktop Linux, when the wrong video…

> But I'm sure 2022 will be "the year of Linux on the desktop", finally :)

With the Steamdeck running Arch Linux, I'm sure you're right. :)

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