USB-C DP alt mode coming! [LWN.net]

USB-C DP alt mode coming!

Posted Feb 18, 2026 15:30 UTC (Wed) by anarcat (subscriber, #66354)
Parent article: An Asahi Linux progress report

For those, like me, peripherally following Asahi, I think the "big one" mentioned in the progress report is worth reporting here in particular.

It seems they have finally implemented the feature "display out via USB-C" AKA "DisplayPort Alt Mode" AKA "using a HDMI adapter on my MacBook Air". This is a big deal. Those are *really* complicated chipsets and it seems they are finally getting there:

In December, Sven gave a talk at 39C3 recounting the Asahi story so far, our reverse engineering process, and what the immediate future looks like for us. At the end, he revealed that the slide deck had been running on an M1 MacBook Air, connected to the venue’s AV system via a USB-C to HDMI adapter!

There are major caveats though, while they say it's "done", they do say "kind of":

All of that said, there is still work to do. Currently, the fairydust branch “blesses” a specific USB-C port on a machine for use with DisplayPort, meaning that multiple USB-C displays is still not possible. There are also some quirks regarding both cold and hot plug of displays. Moreover, some users have reported that DCP does not properly handle certain display setups, variously exhibiting incorrect or oversaturated colours or missing timing modes.

Still, as someone who spends most days typing on this keyboard hooked up to a Dell monitor hooked up to a Framework 13 laptop over a *single* USB-C cable, this is *really* promising and finally makes me wonder if I *will* ever get a Mac laptop. That was the biggest deal breaker for me before: this is the new "dock station", except instead of a clunky proprietary hunk of plastic and circuit boards, it's a single USB-C (40gbps, not all are created equal) connector. Good job, Asahi people, really impressive, as always.

to post comments

USB-C DP alt mode coming!

Posted Feb 19, 2026 4:25 UTC (Thu) by rsidd (subscriber, #2582) [Link] (15 responses)

If Apple were actively supporting the Asahi project I would maybe, perhaps consider an Apple for my next laptop, but as things stand, no. Apple has deigned to allow booting a different OS and that's it. Ironic since Apple has benefited so much from the larger open source ecosystem.

But even if they did offer that support, I would like to have a laptop with three trackpad buttons (like my current Thinkpad), or at least two; and a touchscreen and pen. Cool as Apple's hardware is in terms of performance and battery life, my 5 year old thinkpad is good enough on both counts, so as long as Apple insists on not including touch on laptops or having more than one touchpad button, I would see it as a downgrade, I think.

And then there are the exorbitant peripherals that mac users are forced to buy.

So I am looking at Asahi with distant interest and admiration, that's all.

USB-C DP alt mode coming!

Posted Feb 19, 2026 4:47 UTC (Thu) by mjg59 (subscriber, #23239) [Link] (14 responses)

The Apple trackpad physical response is entirely haptic - there's no physical button at all any more. Software is absolutely free to track finger position when there's a press and turn that into as many buttons as you want. Doesn't help at all with touchscreen or hardware documentation or anything, obviously.

USB-C DP alt mode coming!

Posted Feb 19, 2026 8:33 UTC (Thu) by ballombe (subscriber, #9523) [Link] (13 responses)

Emulated buttons are not very usable without a visual or tactile cue where the buttons borders are.

USB-C DP alt mode coming!

Posted Feb 19, 2026 8:52 UTC (Thu) by Cyberax (✭ supporter ✭, #52523) [Link] (11 responses)

Modern touchpads often just use a double-finger click for the right mouse button.

USB-C DP alt mode coming!

Posted Feb 19, 2026 9:13 UTC (Thu) by rsidd (subscriber, #2582) [Link] (10 responses)

I guess I'm just old fashioned: I prefer physical controls wherever possible (touchpad buttons, AC controls in the car, ...) I regret I can no longer get a good phone with a physical qwerty keypad (I have a Blackberry Key2 but it is stuck on android 8 and not usable with many new apps, so reluctantly "upgraded"). Glad that Apple and others still supply physical keyboards instead of a second touchscreen.

USB-C DP alt mode coming!

Posted Feb 19, 2026 14:16 UTC (Thu) by mathstuf (subscriber, #69389) [Link]

The Onion already reported on keyboard-less Apple devices: https://www.youtube.com/watch?v=9BnLbv6QYcA

Also, I have historically *detested* Apple trackpads. However, with Asahi and libinput configurations they become…bearable. Still not great, but bearable.

USB-C DP alt mode coming!

Posted Feb 19, 2026 18:17 UTC (Thu) by Cyberax (✭ supporter ✭, #52523) [Link] (8 responses)

I used to spend a lot of time customizing Apple touchpads to simulate the physical touch zones for the right/middle clicks. But I've given up when their touchpads became so large that it's actually easier to double-finger-tap.

Now I feel uncomfortable when I need to work on a small touchpad on my other laptop.

USB-C DP alt mode coming!

Posted Feb 19, 2026 21:27 UTC (Thu) by zdzichu (subscriber, #17118) [Link] (7 responses)

I can't stop wondering why people find MacBook touchpads so great. I have a work Mac and Macos X is unusable beyond simple clicking.
Specifically, when I have multiple files selected in Finder and try to move them, following will happen randomly:
- all but one file get deselected
- all files will be opened
- the selection will be expanded to other files
- rename action will trigger.
Completely random & unusable. I'm carrying my mouse if I need to do anything more than using keyboard only.
On my private Thinkpad with Fedora touchpad works perfectly.

USB-C DP alt mode coming!

Posted Feb 21, 2026 5:42 UTC (Sat) by raven667 (subscriber, #5198) [Link] (3 responses)

> I can't stop wondering why people find MacBook touchpads so great.

I think they used to be a lot better than the other hardware you could buy, Apple was always putting in top-end Synaptics touchpads when other laptop makers were still using PS/2 emulation and skimping out (cheap keyboards, no backlight, poor screen, missing ports, bad microphones/speakers/webcams, etc.) but now most vendors use the same higher-end parts and there are good drivers for them and the quality of Apple hasn't been increasing, it's been slipping IMHO.

USB-C DP alt mode coming!

Posted Feb 21, 2026 12:03 UTC (Sat) by Wol (subscriber, #4433) [Link]

Yup. Back in the day, there were two schools of thought - (1) Apple are horribly expensive, and (2) Apple are value for money - you get what you pay for.

I don't remember people complaining at all that they were overpriced.

Cheers,
Wol

USB-C DP alt mode coming!

Posted Feb 21, 2026 13:52 UTC (Sat) by rsidd (subscriber, #2582) [Link] (1 responses)

Apple's main advantage now is the M-series chips. If they had stuck with Intel they would have been clearly inferior, in terms of hardware, to Windows laptops.

USB-C DP alt mode coming!

Posted Feb 21, 2026 16:24 UTC (Sat) by pizza (subscriber, #46) [Link]

> Apple's main advantage now is the M-series chips

...along with their tight vertical integration of the OS and platform tools.

Take away MacOS and (as TFA indicates) even the first-gen M-series Macs are objectively inferior to their Intel/AMD competition.

USB-C DP alt mode coming!

Posted Feb 22, 2026 6:46 UTC (Sun) by comex (subscriber, #71521) [Link] (2 responses)

I'm guessing you're pressing down and dragging with the same finger. The OS also lets you press down with one finger and swipe with another finger, which I find a lot less awkward especially when dragging long distances.

That said, getting rename means you're pressing too hard and getting a force click, which is something you can get used to.

USB-C DP alt mode coming!

Posted Feb 23, 2026 5:45 UTC (Mon) by raven667 (subscriber, #5198) [Link]

Honestly I think we can run into the case where there are too many operations overloaded in too few controls such that it's very possible to never learn all the different gestures, and only trigger them by accident, then the touchpad becomes a poor tool tool; spooky, frustrating and imprecise.

USB-C DP alt mode coming!

Posted Feb 23, 2026 6:51 UTC (Mon) by zdzichu (subscriber, #17118) [Link]

I'm not really sure how can I "press too hard". I'm aware that macbook touchpad has no physical click, it's generated by little vibration motors.

USB-C DP alt mode coming!

Posted Feb 19, 2026 21:30 UTC (Thu) by mjg59 (subscriber, #23239) [Link]

My current Thinkpad has no button markings (tactile or otherwise) and I haven't had a problem.