pci: restore configuration state after resetting a detached child
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Authored by nick_spun.io on Mon, Sep 7, 9:29 PM.

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Reviewers

adrian
kbowling
jhb

Summary

pcie_flr() saves and restores nothing; pairing it with
pci_save_state() and pci_restore_state() is the caller's job. On the
DEVF_RESET_DETACH path of pci_reset_child(), device_detach() saves
through pci_child_detached() and nothing restores. The only restore,
BUS_RESET_POST(), runs when pcie_flr() reports that no reset was
performed.

An FLR returns configuration space to its defaults, so the reprobe
runs against a function whose BARs read zero.

Restore the saved state before reprobing.

Diff Detail

Repository

rG FreeBSD src repository

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Unit

Tests Skipped

Build Status

Buildable 76655
Build 73538: arc lint + arc unit

Event Timeline

nick_spun.io created this revision.Mon, Sep 7, 9:29 PM

Herald added a subscriber: imp. · View Herald TranscriptMon, Sep 7, 9:29 PM

nick_spun.io requested review of this revision.Mon, Sep 7, 9:29 PM

Harbormaster completed remote builds in B76655: Diff 186179.Mon, Sep 7, 9:29 PM

nick_spun.io added reviewers: adrian, kbowling.Mon, Sep 7, 9:30 PM

nick_spun.io added a project: PCI.

bz added a reviewer: jhb.Mon, Sep 7, 9:31 PM

Hmmm, so in theory device_detach() might power off the child. I guess that's ok. I have some WIP that will "fix" this more properly by having device_probe_and_attach() invoke a pre-probe bus_if.m method that for PCI restores the saved state that would handle this transparently, but this is ok for now.

sys/dev/pci/pci.c
7330	Hmm, for DS_BUSY this just bogusly returns 0 without detaching the device. I think this needs to be `>= DS_ATTACHED`.

Revision Contents
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Path

Size

sys/

dev/

pci/

pci.c

6 lines

Diff 186179

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pci: restore configuration state after resetting a detached childNeeds ReviewPublicActions