pci: add quirk to disable FLR
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Authored by bz on Sep 25 2025, 12:57 PM.

Details

Reviewers

jhb
imp
emaste

Commits

rGcafb77e9e0d4: pci: add quirk to disable Function-Level Reset (FLR)
rG3bd015a1a918: pci: add quirk to disable Function-Level Reset (FLR)
rG4c0e53aced22: pci: add quirk to disable Function-Level Reset (FLR)

Summary

MediaTek mt76 WiFi cards are advertising FLR support but after issuing
a FLR the chipset is gone. Add a quirk so we can disable FLR. The
current reset code will automatically fall back to a power reset.

This makes the card show up under bhyve where before it would just not
be discovered at all. That should make wifibox work for it and will help
development for mt76 as no dedicated machine is needed anymore.
We will likely need to add more PCI vendor/device IDs once we can test
the other device IDs.

Event: EuroBSDCon Devsummit 2025
After a lot of help from: jhb
Really implemented by: jhb (I just typed and tested)
MFC after: 3 days

Diff Detail

Repository

rG FreeBSD src repository

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Lint Passed

Unit

No Test Coverage

Build Status

Buildable 67530
Build 64413: arc lint + arc unit

Event Timeline

bz created this revision.Sep 25 2025, 12:57 PM

Herald added a subscriber: imp. · View Herald TranscriptSep 25 2025, 12:57 PM

bz requested review of this revision.Sep 25 2025, 12:57 PM

Harbormaster completed remote builds in B67320: Diff 162817.Sep 25 2025, 12:57 PM

imp accepted this revision.Sep 25 2025, 1:06 PM

This revision is now accepted and ready to land.Sep 25 2025, 1:06 PM

@jhb any comments? I'll wait a few more days ..

can we expand 'Function Level Reset' somewhere in a code comment?

Ah, it is in pcie_flr's description. But perhaps still worth including in the #define PCI_QUIRK_DISABLE_FLR comment?

In D52728#1206608, @emaste wrote:

Ah, it is in pcie_flr's description. But perhaps still worth including in the #define PCI_QUIRK_DISABLE_FLR comment?

Expanding on first use would be good practice :) I agree. Will do once I am at my final destination.

Expand FLR at the quirk definition as suggested by @emaste.

This revision now requires review to proceed.Oct 3 2025, 7:37 PM

Harbormaster completed remote builds in B67530: Diff 163488.Oct 3 2025, 7:37 PM

@emaste this better now?

emaste accepted this revision.Oct 4 2025, 6:10 PM

This revision is now accepted and ready to land.Oct 4 2025, 6:10 PM

Closed by commit rG4c0e53aced22: pci: add quirk to disable Function-Level Reset (FLR) (authored by bz). · Explain WhyOct 4 2025, 6:30 PM

This revision was automatically updated to reflect the committed changes.

bz added a commit: rG4c0e53aced22: pci: add quirk to disable Function-Level Reset (FLR).

bz added a commit: rG3bd015a1a918: pci: add quirk to disable Function-Level Reset (FLR).Oct 20 2025, 6:34 PM

cperciva added a commit: rGcafb77e9e0d4: pci: add quirk to disable Function-Level Reset (FLR).Oct 21 2025, 5:48 AM