@sven@social.treehouse.systems

Sven Peter @sven@social.treehouse.systems · Jun 04, 2026

Replying to @zekjur@mas.to

@zekjur@mas.to ah nice, that looks very useful

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Sven Peter @sven@social.treehouse.systems · Jun 04, 2026

I'm considering coming to #GPN24 on saturday or sunday for half a day or so since I live relatively close by. how easy is it to get a day pass? and anyone there who'd like to meet and chat?

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Sven Peter @sven@social.treehouse.systems · May 03, 2026

Replying to @shac@ioc.exchange

@shac I could begrudgingly live with stuff like temperature control behind touch buttons but what I really hate is when stuff like cruise control is a stupid touch button on the steering wheel as well like on my current Volkswagen. There’s a 50:50 chance that I change the speed by either 1kph or 10kph because their poor excuse for pressure sensitive touch just doesn’t work at all and I still have to briefly look at the steering wheel instead of feeling the dumb button.

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Sven Peter @sven@social.treehouse.systems · Apr 20, 2026

Replying to @shac@ioc.exchange

@shac i see we may have made similar mistakes in the past. Deleting all recipients is the first thing I do when I already feel annoyed before even writing the first word in my reply

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Sven Peter @sven@social.treehouse.systems · Jan 30, 2026

Replying to @elly@donotsta.re

@elly i just don’t understand why these charging stations have to be different that gas stations 😕 They are a mess in .de as well

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Sven Peter @sven@social.treehouse.systems · Jan 19, 2026

Replying to @neobrain@mastodon.social

@neobrain sure! I haven’t ordered stickers yet and the ones we had are all gone so probably no :(

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Sven Peter @sven@social.treehouse.systems · Jan 13, 2026

Replying to @awws@mastodon.social

@awws asciiflow.com and then some manual adjustments of the ascii output in some random text editor

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Sven Peter @sven@social.treehouse.systems · Jan 12, 2026

Replying to @lkundrak@metalhead.club

@lkundrak that would be much more enjoyable than the mess I’m dealing with here :D

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Sven Peter @sven@social.treehouse.systems · Jan 11, 2026

Replying to @wolf480pl@mstdn.io

@wolf480pl no, I didn't draw these lines because I only wanted to focus on USB4/TBT for that picture

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Sven Peter @sven@social.treehouse.systems · Jan 11, 2026

Replying to @wolf480pl@mstdn.io

@wolf480pl there's a mux inside the type-c PHY that deals with that. usually there would be another line from the display crossbar and from dwc3 to that phy

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Sven Peter @sven@social.treehouse.systems · Jan 11, 2026

Replying to @sven@social.treehouse.systems

USB4 allows tunneling of USB3, PCIe and DisplayPort and all that is managed by a Host Router. On Apple Silicon that thing is called acio. The host router contains various protocol adapters which convert the incoming data from e.g. PCIe to the tunneled package format and combines that stream with other tunneled protocols to send it out to the Type-C PHY. The PHY then converts the packets to the on-wire protocol sent over the Type-C port. ACIO also contains an IOMMU and the Native Host Interface (NHI) which controls setting up all these tunnels. This is reason why supporting that entire thing is so complicated: All the various components have to interact with each other and on x86 machines that's mostly abstracted away by firmware running on the router. Here, we don't get that luxury and have to implement all the management ourselves. That also means the first Thunderbolt series will be very boring for end-user: It'll just be the Host Router and the NHI such that tunnels can be established. They will be useless though before we then later implement the protocol adapters. (2/2)

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Sven Peter @sven@social.treehouse.systems · Jan 11, 2026

Working on USB4 for #AsahiLinux and documenting the various components right now. Here's a simplified ASCII drawing: (1/2)

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Sven Peter @sven@social.treehouse.systems · Jan 10, 2026

Replying to @Aissen@social.treehouse.systems

@Aissen yes, absolutely!

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Sven Peter @sven@social.treehouse.systems · Jan 10, 2026

Replying to @vbabka@mastodon.social

@vbabka @ljs @neal likewise! looks like I get to physically meet a few people I’ve only met online before there!

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Sven Peter @sven@social.treehouse.systems · Jan 10, 2026

Looks like I'll be at #FOSDEM this year! I will probably arrive Friday evening and leave Sunday afternoon. Happy to meet and chat about #asahilinux or anything else.

I blame @vbabka@mastodon.social, @ljs@mastodonapp.uk and @neal@social.gompa.me for luring me there :D

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Sven Peter @sven@social.treehouse.systems · Jan 08, 2026

Replying to @sven@social.treehouse.systems

And the (likely) real fixes: https://lore.kernel.org/asahi/20260108-atcphy-coldboot-fix-v1-1-01c41c6e84f2@kernel.org/T/#u and https://lore.kernel.org/asahi/20260108-dwc3-apple-usb2phy-fix-v1-1-5dd7bc642040@kernel.org/T/#u macOS briefly bringing up dwc3 and tearing it down again with no device connected was just a red herring, no idea why that happens.

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Sven Peter @sven@social.treehouse.systems · Jan 07, 2026

Replying to @janne@social.treehouse.systems

@janne yup, it’s just suspicious that at least this old macOS I looked at goes through a similar sequence even when nothing is connected to the usb port

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Sven Peter @sven@social.treehouse.systems · Jan 07, 2026

Replying to @gameshack_@infosec.exchange

@gameshack_ @janne these things don't happen on purpose. what usually happens is that some silicon bug is found very late e.g. during bringup and it's cheaper and easier to just work around it in software than risking another silicon revision trying to fix it

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Sven Peter @sven@social.treehouse.systems · Jan 07, 2026

Replying to @bakkus@bitbang.social

@bakkus @janne we're still not sure if this is actually what's going on and need to do more tests, but maybe some kind of reset?

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Sven Peter @sven@social.treehouse.systems · Jan 07, 2026

Debugging some #asahilinux USB issues with @janne@social.treehouse.systems and right now it looks like ATCPHY is even more cursed than we thought: At boot time, macOS powers up the usb2 PHY once, switches it to host mode and immediately shuts it down again even when no device is connected. I missed this so far but it looks like we actually need this if we want usb2 devices plugged in during boot to work reliably 🙃

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Sven Peter @sven@social.treehouse.systems · Jan 01, 2026

Replying to @cperon@mstdn.social

@cperon yeah, I’m aware of it. It should probably be added to our documentation somewhere

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Sven Peter @sven@social.treehouse.systems · Dec 31, 2025

Replying to @cperon@mstdn.social

@cperon lol, yeah, we could try a very cursed thing as well: put the m4 kernel onto a m3 with all custom ISA stuff enabled, trap all MMIO and redirect it to the m4 in raw boot mode. Would be very slow if it works at all :D

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Sven Peter @sven@social.treehouse.systems · Dec 31, 2025

Replying to @andrewbriscoe@mastodon.social

@andrewbriscoe tldr: it’s gonna be possible but take some time, new contributors are making early progress with m3 and we have some rough ideas for how to tackle m4. no promises on timeline ofc :)

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Sven Peter @sven@social.treehouse.systems · Dec 31, 2025

For those who missed my #Asahilinux #39c3 talk, it's available at https://media.ccc.de/v/39c3-asahi-linux-porting-linux-to-apple-silicon now.

I've also just pushed my slides to https://github.com/svenpeter42/39c3 and uploaded them as PDF to https://cfp.cccv.de/39c3/talk/YGHB9K/

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Sven Peter @sven@social.treehouse.systems · Dec 30, 2025

3.5 hours until my talk about #asahilinux which will be recorded and also live streamed at https://streaming.media.ccc.de/39c3/one

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Sven Peter @sven@social.treehouse.systems · Oct 26, 2025

Replying to @sven@social.treehouse.systems

Like last time this does NOT contain Thunderbolt or DP-AltMode support yet. It's last big piece of code I wrote that's only been in our downstream trees though. Once this is upstream, I can finally focus on new features :-)

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Sven Peter @sven@social.treehouse.systems · Oct 26, 2025

Now that the Apple Silicon dwc3 driver is in -next it's time to continue with the Type-C PHY driver, which is the last part required for upstream USB3:

https://lore.kernel.org/asahi/20251026-b4-atcphy-v1-0-f81b1225f9c6@kernel.org/

#asahilinux #linux

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Sven Peter @sven@social.treehouse.systems · Oct 15, 2025

Replying to @sven@social.treehouse.systems

Looks like it’s mostly ready to be merged, just has to be rebased on usb-next! 🥳 This is another example why sending these patches that we have upstream is so important: The feedback I got from the dwc3 maintainer Thinh made the code much nicer and we don’t have to worry about unrelated changes in dwc3 breaking Apple Silicon support with the new approach he suggested now. It also helped me figure out where SUSPHY is actually required and made the PIPE handler dance much more stable. This will also simplify the atcphy code a little bit. #asahilinux

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Sven Peter @sven@social.treehouse.systems · Oct 13, 2025

Just sent the next version of the Apple Silicon USB3 series, this time only the dwc3 changes: https://lore.kernel.org/asahi/20251013-b4-aplpe-dwc3-v1-0-12a78000c014@kernel.org/

After this, only the PHY itself is missing which I'll send next.

#asahilinux

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Sven Peter @sven@social.treehouse.systems · Sep 10, 2025

Replying to @liangqi@mastodon.social

@liangqi so?

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Sven Peter @sven@social.treehouse.systems · Sep 07, 2025

Replying to @Sobex@social.sciences.re

@Sobex it’s mostly software engineering at this point for both except for some small details here and there I guess

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Sven Peter @sven@social.treehouse.systems · Sep 07, 2025

Replying to @sven@social.treehouse.systems

Since there’s been some confusion: this does *not* enable DisplayPort over these connectors or Thunderbolt. It only brings up the PHY correctly. For DisplayPort work on DCP is needed and for Thunderbolt the native host interface and finally the PCIe controller need to be brought up. This series is just the first step required for both.

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Sven Peter @sven@social.treehouse.systems · Sep 06, 2025

Replying to @curious@floss.social

@curious yup, we may know best what quirks are required to make some generic drivers work on Apple hardware but Thinh has a much better understanding of dwc3 and has probably seen half a dozen different variants. Experience like that is incredibly valuable.

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Sven Peter @sven@social.treehouse.systems · Sep 06, 2025

Just sent out v2 of the USB3 and Type-C PHY support

https://lore.kernel.org/all/20250906-atcphy-6-17-v2-0-52c348623ef6@kernel.org/

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Sven Peter @sven@social.treehouse.systems · Aug 28, 2025

Replying to @vbabka@mastodon.social

@vbabka@mastodon.social @josefbacik@hachyderm.io I’m sure with the right prompt some LLM is totally going to go from commit id to relevant discussion on lore! No more need for Link: tags!

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Sven Peter @sven@social.treehouse.systems · Aug 21, 2025

Replying to @edward@indieweb.social

@edward @AsahiLinux yes, this is the first dependency for external screens. Final support will also require DCP which is still a lot of work to be done.

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Sven Peter @sven@social.treehouse.systems · Aug 21, 2025

Replying to @sebby2k@mastodon.gamedev.place

@sebby2k I believe synopsys is mostly to blame for this one. I think the phy can actually be reconfigured without a power cycle but dwc3 really hates that. The Linux driver for that controller already a few dozen quirks so this one maybe isn’t too surprising. There’s also a stateful eUSB2 (low voltage USB2 for modern SoCs) to USB2 converter on the board that also messes things up.

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Sven Peter @sven@social.treehouse.systems · Aug 21, 2025

Replying to @sebby2k@mastodon.gamedev.place

@sebby2k yeah, they also power cycle everything. it's a truly weird design choice and I'd really like to know how this happened and why they haven't fixed it yet.

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Sven Peter @sven@social.treehouse.systems · Aug 21, 2025

Replying to @trollkatt@mastodon.online

@trollkatt LKML can occasionally be quite abrasive and toxic (and that’s the mails you then see amplified all over the place) but most of the time the feedback is useful

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Sven Peter @sven@social.treehouse.systems · Aug 21, 2025

I've finally just submitted the RFC series for USB3 support on Apple Silicon machines. RFC because the entire Type-C machinery spans multiple subsystems and has quite a few quirks which makes the entire thing rather annoying to deal with and I'm not 100% convinced about the current approach.

This also includes some initial work for DisplayPort-altmode and USB4/Thunderbolt but both will require much more work after this is upstream, so don't get your hopes up just yet.

https://lore.kernel.org/asahi/20250821-atcphy-6-17-v1-0-172beda182b8@kernel.org/

#asahilinux #linux

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Sven Peter @sven@social.treehouse.systems · Jun 26, 2025

Replying to @patronics@social.treehouse.systems

@patronics no and no.

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Sven Peter @sven@social.treehouse.systems · Apr 04, 2025

Replying to @xsk@social.treehouse.systems

@xsk an alternative would be to hijack XNUs exception handlers and pagetable code and patch the tracing in there. we’ll see.

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Sven Peter @sven@social.treehouse.systems · Apr 04, 2025

Looks like M4 support for #asahilinux is going be rather painful. We’re still focusing on upstreaming M1/M2 support but other people have been trying to bring up m1n1 on M4 and it looks like a few things changed:

When configuring a macho boot object we now get dropped into an environment where Apple’s SPTM is running in GL2 and we are supposed to talk to it from EL2 with MMU already enabled to setup pagetables. This neither works for Linux nor for running XNU under our hypervisor to reverse engineer the new hardware.

When configuring a raw boot object we’re dropped into EL2 with GL2 and most (all?) Apple specific extensions disabled. This is totally fine for Linux but we can’t run XNU under our hypervisor that we use to reverse engineer the hardware in this state. This also seems to be broken for >=15.2 right now because it probably isn’t very well tested 😕

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