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thunderbolt: apple: do not start the NHI without its DART - #1150
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The NHI and its DART are both children of the ACIO and are created together when the router starts. The DART normally binds first, and the driver core defers the NHI until it has. Once the core has stopped waiting for missing suppliers, though (for example, the DART driver is a module that is not loaded yet when a cable is plugged in), the NHI probes without an IOMMU and would hand the hardware physical ring addresses. Refuse to probe an NHI that has iommus but is not attached to an IOMMU domain. Report it through the boot status as well, so that the ACIO fails this start right away with -EPROBE_DEFER instead of waiting for the 10 s NHI boot timeout; the next connection retries. Signed-off-by: Dmitriy <noc@pimk.in> Assisted-by: LLM
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apple_nhi_probe()now refuses to start an NHI that hasiommusbut isn't attached to an IOMMU yet. That happens when the DART driver is a module that isn't loaded when a cable is plugged in, after the driver core has stopped waiting for suppliers. The rings then never run untranslated. The NHI reports-EPROBE_DEFERthrough the boot status, so the ACIO start fails right away instead of after the 10 s NHI timeout, and the next connection retries.The earlier first commit here, which compared the T8142 NHI generation as a boolean, is dropped: 8aaab09 rewrote that check as
(t8142 || t6040), which is boolean already.Tested on: J704 (MacBook Pro 14-inch, M5), 2026-11-07, with a Mac mini (Mac16,10) on a Thunderbolt cable:
409f00000.nhibinds tothunderbolt-apple-nhiin its IOMMU group, the XDomain host is found andthunderbolt0comes up with an address. The change has been in my J704 kernel for days, with Thunderbolt networking to the Mac mini. Rebased ontointegration/aurora9cfd38d;thunderbolt/apple.obuilds clean withW=1there.Prepared with Claude Opus 5.5; tested by me on the hardware.