[REGRESSION] PCI: Dynamic OF node creation hangs on invalid bridge configuration

[REGRESSION] PCI: Dynamic OF node creation hangs on invalid bridge configuration

[Angel J]

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Hello,

This regression was introduced in v6.17-rc1 and remains in the dynamic
PCI OF node code. Linux 6.18 fails very early during boot on my Dell XPS
8940 when CONFIG_PCI_DYNAMIC_OF_NODES=y. The display goes black before
any useful console or pstore output appears, and the machine remains
hung.

Disabling CONFIG_PCI_DYNAMIC_OF_NODES makes the same kernel boot normally.
Linux v6.19-rc5 also boots because the RP1 driver stopped selecting that
option, not because the dynamic PCI OF node code changed.

Hardware:

  System: Dell XPS 8940, board 0K3CM7, BIOS 2.27.1 (2025-04-03)
  CPU: Intel Core i7-11700 (Rocket Lake)
  Triggering device: 0000:00:00.0, Intel 8086:4c43
  Firmware boot: UEFI, ACPI-based x86_64

Test results:

  Linux 6.12.103: good
  Linux v6.17-rc1: bad
  Linux 6.18.44, CONFIG_PCI_DYNAMIC_OF_NODES=y: bad
  Linux 6.18.44, CONFIG_PCI_DYNAMIC_OF_NODES=n: good
  Linux 6.18.44, CONFIG_PCI_DYNAMIC_OF_NODES=y, skip invalid bridge: good
  Linux v6.19-rc4: bad
  Linux v6.19-rc5: good
  Linux 4621c338d33f: bad
  Linux e55feea3a03a: good

The first-parent boundary between the last two tests is:

  e55feea3a03a ("Merge tag 'soc-fixes-6.19' ...")

That merge contains ce26f588c831 ("misc: rp1: drop overlay support"), which
removes:

  select PCI_DYNAMIC_OF_NODES

from MISC_RP1. The generated configurations differed only by:

  -CONFIG_PCI_DYNAMIC_OF_NODES=y
  +# CONFIG_PCI_DYNAMIC_OF_NODES is not set

CONFIG_MISC_RP1=m in both. The known-bad 4621c338d33f and Linux 6.18.44
both boot after disabling PCI_DYNAMIC_OF_NODES (and MISC_RP1, whose Kconfig
select otherwise forces it on).

There is no RP1 device in this machine, and its driver does not probe.
MISC_RP1 affects this x86 system only because its Kconfig select enables
PCI_DYNAMIC_OF_NODES globally.

I narrowed the hang to dynamic OF node creation for 0000:00:00.0
(8086:4c43), the Intel Rocket Lake-S integrated memory controller. On
this machine it reports PCI class 0604 and header type 1, but it is bound
to icl_uncore and is not a usable forwarding bridge:

  Bus: primary=ff, secondary=ff, subordinate=ff
  I/O and memory bridge windows: invalid/all ones
  kernel: bridge configuration invalid ([bus ff-ff]), reconfiguring

A minimal dynamic node for this device boots. Adding only
device_type="pci" makes it hang. Full PCI dynamic OF node generation also
boots when only 0000:00:00.0 is skipped.

I also tested a generic guard in of_pci_make_dev_node(). It reads
PCI_PRIMARY_BUS and skips node creation if the primary bus does not match
pdev->bus->number, the secondary bus is not greater than the primary bus,
or the secondary bus is greater than the subordinate bus. Linux 6.18.44
boots with CONFIG_PCI_DYNAMIC_OF_NODES=y and logs:

  pci 0000:00:00.0: skipping dynamic OF node for invalid bridge

The regression was introduced by 49d63971f963 in v6.17-rc1. Commit
ce26f588c831 made v6.19-rc5 boot by removing MISC_RP1's select of
PCI_DYNAMIC_OF_NODES. That avoids the failing path in the tested
configuration but does not change of_pci_make_dev_node().

I do not have a log from the failed boots. No output appeared with
earlyprintk=efi,keep, keep_bootcon, ignore_loglevel, loglevel=8,
initcall_debug, and EFI pstore enabled. Blacklisting both GPU drivers and
disabling the Intel IOMMU did not make the bad kernel boot.

Should of_pci_make_dev_node() reject devices with invalid bridge bus
configuration, or should 8086:4c43 use a device-specific quirk? I can
prepare and test a patch for either approach. For Linux 6.18 stable,
would that fix be preferable to backporting ce26f588c831 and its
dependencies?

#regzbot introduced: 49d63971f963
#regzbot title: PCI_DYNAMIC_OF_NODES early boot hang on ACPI x86

Thanks,
Angel J






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Re: [REGRESSION] PCI: Dynamic OF node creation hangs on invalid bridge configuration

[Angel J]

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Hello,

A friendly ping on this regression. It still affects Linux 6.18, and
the tested invalid-bridge guard allows the machine to boot with
CONFIG_PCI_DYNAMIC_OF_NODES=y.

Is any additional information or testing needed from me?

Thanks,
Angel



On Saturday, August 22nd, 2026 at 19:14, Angel J <iamanaws@httpd.dev> wrote:

> Hello,
> 

> This regression was introduced in v6.17-rc1 and remains in the dynamic
> PCI OF node code. Linux 6.18 fails very early during boot on my Dell XPS
> 8940 when CONFIG_PCI_DYNAMIC_OF_NODES=y. The display goes black before
> any useful console or pstore output appears, and the machine remains
> hung.
> 

> Disabling CONFIG_PCI_DYNAMIC_OF_NODES makes the same kernel boot normally.
> Linux v6.19-rc5 also boots because the RP1 driver stopped selecting that
> option, not because the dynamic PCI OF node code changed.
> 

> Hardware:
> 

>   System: Dell XPS 8940, board 0K3CM7, BIOS 2.27.1 (2025-04-03)
>   CPU: Intel Core i7-11700 (Rocket Lake)
>   Triggering device: 0000:00:00.0, Intel 8086:4c43
>   Firmware boot: UEFI, ACPI-based x86_64
> 

> Test results:
> 

>   Linux 6.12.103: good
>   Linux v6.17-rc1: bad
>   Linux 6.18.44, CONFIG_PCI_DYNAMIC_OF_NODES=y: bad
>   Linux 6.18.44, CONFIG_PCI_DYNAMIC_OF_NODES=n: good
>   Linux 6.18.44, CONFIG_PCI_DYNAMIC_OF_NODES=y, skip invalid bridge: good
>   Linux v6.19-rc4: bad
>   Linux v6.19-rc5: good
>   Linux 4621c338d33f: bad
>   Linux e55feea3a03a: good
> 

> The first-parent boundary between the last two tests is:
> 

>   e55feea3a03a ("Merge tag 'soc-fixes-6.19' ...")
> 

> That merge contains ce26f588c831 ("misc: rp1: drop overlay support"), which
> removes:
> 

>   select PCI_DYNAMIC_OF_NODES
> 

> from MISC_RP1. The generated configurations differed only by:
> 

>   -CONFIG_PCI_DYNAMIC_OF_NODES=y
>   +# CONFIG_PCI_DYNAMIC_OF_NODES is not set
> 

> CONFIG_MISC_RP1=m in both. The known-bad 4621c338d33f and Linux 6.18.44
> both boot after disabling PCI_DYNAMIC_OF_NODES (and MISC_RP1, whose Kconfig
> select otherwise forces it on).
> 

> There is no RP1 device in this machine, and its driver does not probe.
> MISC_RP1 affects this x86 system only because its Kconfig select enables
> PCI_DYNAMIC_OF_NODES globally.
> 

> I narrowed the hang to dynamic OF node creation for 0000:00:00.0
> (8086:4c43), the Intel Rocket Lake-S integrated memory controller. On
> this machine it reports PCI class 0604 and header type 1, but it is bound
> to icl_uncore and is not a usable forwarding bridge:
> 

>   Bus: primary=ff, secondary=ff, subordinate=ff
>   I/O and memory bridge windows: invalid/all ones
>   kernel: bridge configuration invalid ([bus ff-ff]), reconfiguring
> 

> A minimal dynamic node for this device boots. Adding only
> device_type="pci" makes it hang. Full PCI dynamic OF node generation also
> boots when only 0000:00:00.0 is skipped.
> 

> I also tested a generic guard in of_pci_make_dev_node(). It reads
> PCI_PRIMARY_BUS and skips node creation if the primary bus does not match
> pdev->bus->number, the secondary bus is not greater than the primary bus,
> or the secondary bus is greater than the subordinate bus. Linux 6.18.44
> boots with CONFIG_PCI_DYNAMIC_OF_NODES=y and logs:
> 

>   pci 0000:00:00.0: skipping dynamic OF node for invalid bridge
> 

> The regression was introduced by 49d63971f963 in v6.17-rc1. Commit
> ce26f588c831 made v6.19-rc5 boot by removing MISC_RP1's select of
> PCI_DYNAMIC_OF_NODES. That avoids the failing path in the tested
> configuration but does not change of_pci_make_dev_node().
> 

> I do not have a log from the failed boots. No output appeared with
> earlyprintk=efi,keep, keep_bootcon, ignore_loglevel, loglevel=8,
> initcall_debug, and EFI pstore enabled. Blacklisting both GPU drivers and
> disabling the Intel IOMMU did not make the bad kernel boot.
> 

> Should of_pci_make_dev_node() reject devices with invalid bridge bus
> configuration, or should 8086:4c43 use a device-specific quirk? I can
> prepare and test a patch for either approach. For Linux 6.18 stable,
> would that fix be preferable to backporting ce26f588c831 and its
> dependencies?
> 

> #regzbot introduced: 49d63971f963
> #regzbot title: PCI_DYNAMIC_OF_NODES early boot hang on ACPI x86
> 

> Thanks,
> Angel J
> 

> 

> 

> 

> 

> 

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Re: [REGRESSION] PCI: Dynamic OF node creation hangs on invalid bridge configuration

[Thorsten Leemhuis]

On 9/1/26 02:59, Angel J wrote:
> A friendly ping on this regression.

Ideally the problem would be fixed, sure. But by your explanation it was
already in mainline and backporting those changes might be too much
churn. But you could try to submit a backport of ce26f588c831 (if that's
all that's needed) to the stable team (or ask somebody to do that for
you), maybe they will puck it up.

And overall: I not entirely sure if this counts as a regression, as you
(if I understood things properly) enabled something new in your .config
(that caused some other hidden problem to show up). That makes it a
non-regression, as, say, new security restrictions (that block things
that used to work) guarded by a new config option could never be
introduced otherwise in Linux.

Ciao, Thorsten

> It still affects Linux 6.18, and
> the tested invalid-bridge guard allows the machine to boot with
> CONFIG_PCI_DYNAMIC_OF_NODES=y.
> 
> Is any additional information or testing needed from me?
> 
> Thanks,
> Angel
> 
> 
> 
> On Saturday, August 22nd, 2026 at 19:14, Angel J <iamanaws@httpd.dev> wrote:
> 
>> Hello,
>>
> 
>> This regression was introduced in v6.17-rc1 and remains in the dynamic
>> PCI OF node code. Linux 6.18 fails very early during boot on my Dell XPS
>> 8940 when CONFIG_PCI_DYNAMIC_OF_NODES=y. The display goes black before
>> any useful console or pstore output appears, and the machine remains
>> hung.
>>
> 
>> Disabling CONFIG_PCI_DYNAMIC_OF_NODES makes the same kernel boot normally.
>> Linux v6.19-rc5 also boots because the RP1 driver stopped selecting that
>> option, not because the dynamic PCI OF node code changed.
>>
> 
>> Hardware:
>>
> 
>>   System: Dell XPS 8940, board 0K3CM7, BIOS 2.27.1 (2025-04-03)
>>   CPU: Intel Core i7-11700 (Rocket Lake)
>>   Triggering device: 0000:00:00.0, Intel 8086:4c43
>>   Firmware boot: UEFI, ACPI-based x86_64
>>
> 
>> Test results:
>>
> 
>>   Linux 6.12.103: good
>>   Linux v6.17-rc1: bad
>>   Linux 6.18.44, CONFIG_PCI_DYNAMIC_OF_NODES=y: bad
>>   Linux 6.18.44, CONFIG_PCI_DYNAMIC_OF_NODES=n: good
>>   Linux 6.18.44, CONFIG_PCI_DYNAMIC_OF_NODES=y, skip invalid bridge: good
>>   Linux v6.19-rc4: bad
>>   Linux v6.19-rc5: good
>>   Linux 4621c338d33f: bad
>>   Linux e55feea3a03a: good
>>
> 
>> The first-parent boundary between the last two tests is:
>>
> 
>>   e55feea3a03a ("Merge tag 'soc-fixes-6.19' ...")
>>
> 
>> That merge contains ce26f588c831 ("misc: rp1: drop overlay support"), which
>> removes:
>>
> 
>>   select PCI_DYNAMIC_OF_NODES
>>
> 
>> from MISC_RP1. The generated configurations differed only by:
>>
> 
>>   -CONFIG_PCI_DYNAMIC_OF_NODES=y
>>   +# CONFIG_PCI_DYNAMIC_OF_NODES is not set
>>
> 
>> CONFIG_MISC_RP1=m in both. The known-bad 4621c338d33f and Linux 6.18.44
>> both boot after disabling PCI_DYNAMIC_OF_NODES (and MISC_RP1, whose Kconfig
>> select otherwise forces it on).
>>
> 
>> There is no RP1 device in this machine, and its driver does not probe.
>> MISC_RP1 affects this x86 system only because its Kconfig select enables
>> PCI_DYNAMIC_OF_NODES globally.
>>
> 
>> I narrowed the hang to dynamic OF node creation for 0000:00:00.0
>> (8086:4c43), the Intel Rocket Lake-S integrated memory controller. On
>> this machine it reports PCI class 0604 and header type 1, but it is bound
>> to icl_uncore and is not a usable forwarding bridge:
>>
> 
>>   Bus: primary=ff, secondary=ff, subordinate=ff
>>   I/O and memory bridge windows: invalid/all ones
>>   kernel: bridge configuration invalid ([bus ff-ff]), reconfiguring
>>
> 
>> A minimal dynamic node for this device boots. Adding only
>> device_type="pci" makes it hang. Full PCI dynamic OF node generation also
>> boots when only 0000:00:00.0 is skipped.
>>
> 
>> I also tested a generic guard in of_pci_make_dev_node(). It reads
>> PCI_PRIMARY_BUS and skips node creation if the primary bus does not match
>> pdev->bus->number, the secondary bus is not greater than the primary bus,
>> or the secondary bus is greater than the subordinate bus. Linux 6.18.44
>> boots with CONFIG_PCI_DYNAMIC_OF_NODES=y and logs:
>>
> 
>>   pci 0000:00:00.0: skipping dynamic OF node for invalid bridge
>>
> 
>> The regression was introduced by 49d63971f963 in v6.17-rc1. Commit
>> ce26f588c831 made v6.19-rc5 boot by removing MISC_RP1's select of
>> PCI_DYNAMIC_OF_NODES. That avoids the failing path in the tested
>> configuration but does not change of_pci_make_dev_node().
>>
> 
>> I do not have a log from the failed boots. No output appeared with
>> earlyprintk=efi,keep, keep_bootcon, ignore_loglevel, loglevel=8,
>> initcall_debug, and EFI pstore enabled. Blacklisting both GPU drivers and
>> disabling the Intel IOMMU did not make the bad kernel boot.
>>
> 
>> Should of_pci_make_dev_node() reject devices with invalid bridge bus
>> configuration, or should 8086:4c43 use a device-specific quirk? I can
>> prepare and test a patch for either approach. For Linux 6.18 stable,
>> would that fix be preferable to backporting ce26f588c831 and its
>> dependencies?
>>
> 
>> #regzbot introduced: 49d63971f963
>> #regzbot title: PCI_DYNAMIC_OF_NODES early boot hang on ACPI x86
>>
> 
>> Thanks,
>> Angel J
>>
> 
>>
> 
>>
> 
>>
> 
>>
> 
>>

Re: [REGRESSION] PCI: Dynamic OF node creation hangs on invalid bridge configuration

[Bjorn Helgaas]

[+to Herve, Lizhi for PCI dynamic OF node stuff]

On Sun, Aug 23, 2026 at 02:14:25AM +0000, Angel J wrote:
> Hello,
> 
> This regression was introduced in v6.17-rc1 and remains in the dynamic
> PCI OF node code. Linux 6.18 fails very early during boot on my Dell XPS
> 8940 when CONFIG_PCI_DYNAMIC_OF_NODES=y. The display goes black before
> any useful console or pstore output appears, and the machine remains
> hung.

Oof, sorry, that's a terrible failure to debug.  Thanks for your
persistence in chasing it.

I don't think 49d63971f963 ("misc: rp1: RaspberryPi RP1 misc driver")
is a likely culprit by itself because there's just nothing there that
looks like it would relate to a Dell XPS 8940.

> Disabling CONFIG_PCI_DYNAMIC_OF_NODES makes the same kernel boot normally.
> Linux v6.19-rc5 also boots because the RP1 driver stopped selecting that
> option, not because the dynamic PCI OF node code changed.
> 
> Hardware:
> 
>   System: Dell XPS 8940, board 0K3CM7, BIOS 2.27.1 (2025-04-03)
>   CPU: Intel Core i7-11700 (Rocket Lake)
>   Triggering device: 0000:00:00.0, Intel 8086:4c43
>   Firmware boot: UEFI, ACPI-based x86_64
> 
> Test results:
> 
>   Linux 6.12.103: good
>   Linux v6.17-rc1: bad
>   Linux 6.18.44, CONFIG_PCI_DYNAMIC_OF_NODES=y: bad
>   Linux 6.18.44, CONFIG_PCI_DYNAMIC_OF_NODES=n: good
>   Linux 6.18.44, CONFIG_PCI_DYNAMIC_OF_NODES=y, skip invalid bridge: good
>   Linux v6.19-rc4: bad
>   Linux v6.19-rc5: good
>   Linux 4621c338d33f: bad
>   Linux e55feea3a03a: good
> 
> The first-parent boundary between the last two tests is:
> 
>   e55feea3a03a ("Merge tag 'soc-fixes-6.19' ...")
> 
> That merge contains ce26f588c831 ("misc: rp1: drop overlay support"), which
> removes:
> 
>   select PCI_DYNAMIC_OF_NODES
> 
> from MISC_RP1. The generated configurations differed only by:
> 
>   -CONFIG_PCI_DYNAMIC_OF_NODES=y
>   +# CONFIG_PCI_DYNAMIC_OF_NODES is not set
> 
> CONFIG_MISC_RP1=m in both. The known-bad 4621c338d33f and Linux 6.18.44
> both boot after disabling PCI_DYNAMIC_OF_NODES (and MISC_RP1, whose Kconfig
> select otherwise forces it on).
> 
> There is no RP1 device in this machine, and its driver does not probe.
> MISC_RP1 affects this x86 system only because its Kconfig select enables
> PCI_DYNAMIC_OF_NODES globally.
> 
> I narrowed the hang to dynamic OF node creation for 0000:00:00.0
> (8086:4c43), the Intel Rocket Lake-S integrated memory controller. On
> this machine it reports PCI class 0604 and header type 1, but it is bound
> to icl_uncore and is not a usable forwarding bridge:
> 
>   Bus: primary=ff, secondary=ff, subordinate=ff
>   I/O and memory bridge windows: invalid/all ones
>   kernel: bridge configuration invalid ([bus ff-ff]), reconfiguring
> 
> A minimal dynamic node for this device boots. Adding only
> device_type="pci" makes it hang. Full PCI dynamic OF node generation also
> boots when only 0000:00:00.0 is skipped.
> 
> I also tested a generic guard in of_pci_make_dev_node(). It reads
> PCI_PRIMARY_BUS and skips node creation if the primary bus does not match
> pdev->bus->number, the secondary bus is not greater than the primary bus,
> or the secondary bus is greater than the subordinate bus. Linux 6.18.44
> boots with CONFIG_PCI_DYNAMIC_OF_NODES=y and logs:
> 
>   pci 0000:00:00.0: skipping dynamic OF node for invalid bridge
> 
> The regression was introduced by 49d63971f963 in v6.17-rc1. Commit
> ce26f588c831 made v6.19-rc5 boot by removing MISC_RP1's select of
> PCI_DYNAMIC_OF_NODES. That avoids the failing path in the tested
> configuration but does not change of_pci_make_dev_node().
> 
> I do not have a log from the failed boots. No output appeared with
> earlyprintk=efi,keep, keep_bootcon, ignore_loglevel, loglevel=8,
> initcall_debug, and EFI pstore enabled. Blacklisting both GPU drivers and
> disabling the Intel IOMMU did not make the bad kernel boot.
> 
> Should of_pci_make_dev_node() reject devices with invalid bridge bus
> configuration, or should 8086:4c43 use a device-specific quirk? I can
> prepare and test a patch for either approach. For Linux 6.18 stable,
> would that fix be preferable to backporting ce26f588c831 and its
> dependencies?

A quirk doesn't sound right because AFAICS there isn't any hardware
defect with the 00:00.0 bridge.

> #regzbot introduced: 49d63971f963
> #regzbot title: PCI_DYNAMIC_OF_NODES early boot hang on ACPI x86
> 
> Thanks,
> Angel J
> 
> 
> 
> 
> 

Re: [REGRESSION] PCI: Dynamic OF node creation hangs on invalid bridge configuration

[Herve Codina]

Hi Angel, Bjorn,

On Thu, 3 Sep 2026 18:17:44 -0500
Bjorn Helgaas <helgaas@kernel.org> wrote:

> [+to Herve, Lizhi for PCI dynamic OF node stuff]
> 
> On Sun, Aug 23, 2026 at 02:14:25AM +0000, Angel J wrote:
> > Hello,
> > 
> > This regression was introduced in v6.17-rc1 and remains in the dynamic
> > PCI OF node code. Linux 6.18 fails very early during boot on my Dell XPS
> > 8940 when CONFIG_PCI_DYNAMIC_OF_NODES=y. The display goes black before
> > any useful console or pstore output appears, and the machine remains
> > hung.  
> 
> Oof, sorry, that's a terrible failure to debug.  Thanks for your
> persistence in chasing it.
> 
> I don't think 49d63971f963 ("misc: rp1: RaspberryPi RP1 misc driver")
> is a likely culprit by itself because there's just nothing there that
> looks like it would relate to a Dell XPS 8940.
> 
> > Disabling CONFIG_PCI_DYNAMIC_OF_NODES makes the same kernel boot normally.
> > Linux v6.19-rc5 also boots because the RP1 driver stopped selecting that
> > option, not because the dynamic PCI OF node code changed.
> > 
> > Hardware:
> > 
> >   System: Dell XPS 8940, board 0K3CM7, BIOS 2.27.1 (2025-04-03)
> >   CPU: Intel Core i7-11700 (Rocket Lake)
> >   Triggering device: 0000:00:00.0, Intel 8086:4c43
> >   Firmware boot: UEFI, ACPI-based x86_64
> > 
> > Test results:
> > 
> >   Linux 6.12.103: good
> >   Linux v6.17-rc1: bad
> >   Linux 6.18.44, CONFIG_PCI_DYNAMIC_OF_NODES=y: bad
> >   Linux 6.18.44, CONFIG_PCI_DYNAMIC_OF_NODES=n: good
> >   Linux 6.18.44, CONFIG_PCI_DYNAMIC_OF_NODES=y, skip invalid bridge: good
> >   Linux v6.19-rc4: bad
> >   Linux v6.19-rc5: good
> >   Linux 4621c338d33f: bad
> >   Linux e55feea3a03a: good
> > 
> > The first-parent boundary between the last two tests is:
> > 
> >   e55feea3a03a ("Merge tag 'soc-fixes-6.19' ...")
> > 
> > That merge contains ce26f588c831 ("misc: rp1: drop overlay support"), which
> > removes:
> > 
> >   select PCI_DYNAMIC_OF_NODES
> > 
> > from MISC_RP1. The generated configurations differed only by:
> > 
> >   -CONFIG_PCI_DYNAMIC_OF_NODES=y
> >   +# CONFIG_PCI_DYNAMIC_OF_NODES is not set
> > 
> > CONFIG_MISC_RP1=m in both. The known-bad 4621c338d33f and Linux 6.18.44
> > both boot after disabling PCI_DYNAMIC_OF_NODES (and MISC_RP1, whose Kconfig
> > select otherwise forces it on).
> > 
> > There is no RP1 device in this machine, and its driver does not probe.
> > MISC_RP1 affects this x86 system only because its Kconfig select enables
> > PCI_DYNAMIC_OF_NODES globally.
> > 
> > I narrowed the hang to dynamic OF node creation for 0000:00:00.0
> > (8086:4c43), the Intel Rocket Lake-S integrated memory controller. On
> > this machine it reports PCI class 0604 and header type 1, but it is bound
> > to icl_uncore and is not a usable forwarding bridge:
> > 
> >   Bus: primary=ff, secondary=ff, subordinate=ff
> >   I/O and memory bridge windows: invalid/all ones
> >   kernel: bridge configuration invalid ([bus ff-ff]), reconfiguring

Is this PCI logs reported with PCI_DYNAMIC_OF_NODES=y or PCI_DYNAMIC_OF_NODES=n
or always whatever the PCI_DYNAMIC_OF_NODES Kconfig value ?

A PCI class 0604 is a PCI-to-PCI bridge.

Something in kernel code prevent the scan of this PCI-to-PCI bridge even if the
kernel tries to reconfigure it. Indeed, the device is "Intel Rocket Lake-S
integrated memory controller" and not a PCI-to-PCI bridge

The of_pci_make_dev_node() is called by the PCI core [1] to create OF node for
bridges.

of_pci_make_dev_node() will set (device_type = "pci" in the created node).

But if the device it is not a bridge, this is obviously wrong (even if I don't
understand why it hangs the system).

Maybe the test done at [1] should be improved to detect those wrong bridges.
and skip the of_pci_make_dev_node() call when a wrong bridge is detected.

[1] https://elixir.bootlin.com/linux/v7.2/source/drivers/pci/bus.c#L355


Best regards,
Hervé